android 代码优化的小细节整理

1，最近在对class InSpect code 的过程中，积累了一些优化代码的经验，分享如下：

在Activity中对TextView进行动态更新显示数据时，如果使用:

RGB_textview.setText(settingData.Image_R + "," + settingData.Image_G + "," + settingData.Image_B);

则Android Studio 会提示：“Do not concatenate text displayed with setText，use resource string with placeholders”，

应改为：

RGB_textview.setText(getString(R.string.RGB_value_string, settingData.Image_R, settingData.Image_G, settingData.Image_B));
<string name="RGB_value_string">%1$d,%2$d,%3$d</string>

不修改也能正常运行，但修改一下会更加规范。

2，

创建一个空白的drawable

myPopupWindow.setBackgroundDrawable(new ColorDrawable(Android.graphics.Color.TRANSPARENT));

I've used a PopupWindow. With this PopupWindow I set the BackgroundDrawable to an empty BitmapDrawable.

When I use the following code it gives a deprecated warning:

<code style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; font-family: Consolas, Menlo, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace, serif; white-space: inherit;"><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">myPopupWindow</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">setBackgroundDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(0, 0, 139); background: transparent;">new</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">BitmapDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">());</span></code>

So I changed it to:

<code style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; font-family: Consolas, Menlo, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace, serif; white-space: inherit;"><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">myPopupWindow</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">setBackgroundDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(0, 0, 139); background: transparent;">new</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">BitmapDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">    getApplicationContext</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">().</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">getResources</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(),</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">    </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Bitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">createBitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="lit" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(128, 0, 0); background: transparent;">0</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">,</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="lit" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(128, 0, 0); background: transparent;">0</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">,</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Bitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Config</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">ARGB_8888</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">)</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"></span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">));</span></code>

This gave me an error that a Bitmap must have a width and height bigger than 0.

Right now I use:

<code style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; font-family: Consolas, Menlo, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace, serif; white-space: inherit;"><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">myPopupWindow</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">setBackgroundDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(0, 0, 139); background: transparent;">new</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">BitmapDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">    getApplicationContext</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">().</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">getResources</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(),</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">    </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Bitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">createBitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="lit" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(128, 0, 0); background: transparent;">1</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">,</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="lit" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(128, 0, 0); background: transparent;">1</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">,</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Bitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Config</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">ARGB_8888</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">)</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"></span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">));</span></code>

And it works. But it just seems a bit wrong to use a 1x1 pixel Bitmap instead of a completely empty one like I want to. Is there another way to actually use an empty BitmapDrawable, instead of one that is 1 by 1 pixels?

down voteaccepted

Ok, instead of

<code style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; font-family: Consolas, Menlo, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace, serif; white-space: inherit;"><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">myPopupWindow</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">setBackgroundDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(0, 0, 139); background: transparent;">new</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">BitmapDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">());</span></code>

OR

<code style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; font-family: Consolas, Menlo, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace, serif; white-space: inherit;"><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">myPopupWindow</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">setBackgroundDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(0, 0, 139); background: transparent;">new</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">BitmapDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">    getApplicationContext</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">().</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">getResources</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(),</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">    </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Bitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">createBitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="lit" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(128, 0, 0); background: transparent;">1</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">,</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="lit" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(128, 0, 0); background: transparent;">1</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">,</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Bitmap</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Config</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">ARGB_8888</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">)</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"></span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">));</span></code>

I just use a background-color that I want to set to the PopupWindow. So for example, one of my PopupWindows just had a few Images without margins in between them, so I just used a Transparent background for it:

<code style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; font-family: Consolas, Menlo, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace, serif; white-space: inherit;"><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">myPopupWindow</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">setBackgroundDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(0, 0, 139); background: transparent;">new</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">ColorDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">android</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">graphics</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Color</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">TRANSPARENT</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">));</span></code>

And for another one I wanted to use a white background anyway, so I've used:

<code style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; font-family: Consolas, Menlo, Monaco, "Lucida Console", "Liberation Mono", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Courier New", monospace, serif; white-space: inherit;"><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">myPopupWindow</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">setBackgroundDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="kwd" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(0, 0, 139); background: transparent;">new</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;"> </span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">ColorDrawable</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">(</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">android</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">graphics</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="typ" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; color: rgb(43, 145, 175); background: transparent;">Color</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">.</span><span class="pln" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">WHITE</span><span class="pun" style="margin: 0px; padding: 0px; border: 0px; vertical-align: baseline; background: transparent;">));</span></code>

3，getcolor（int  id）会在6.0报警告，可以用

ContextCompat.getColor(this,R.color.tips_phone)替换