Android 开发笔记

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1,PopupWindow消失的问题

在fragment中使用PopupWindow，点击它区域外的地方，让其自动隐藏。

 private PopupWindow popupWindow;    private void showPopWindow() {        if(popupWindow == null){            View pop_view = activity.getLayoutInflater().inflate(R.layout.popwin_order_list, null);            popupWindow = new PopupWindow(pop_view, UIUtils.dip2px(context,100),  RelativeLayout.LayoutParams.WRAP_CONTENT,true);            initRadioButton(pop_view);        }        popupWindow.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));        popupWindow.setOutsideTouchable(true);//该属性设置为true,则在点击屏幕的空白位置也会退出        popupWindow.setFocusable(true);        popupWindow.setTouchable(true);        popupWindow.showAsDropDown(toolbar.getTvRight2(), -80, 0);    }

2,FragmentTabHost切换其它fragment，后退crash

布局文件

<android.support.v4.app.FragmentTabHost        android:id="@android:id/tabhost"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_weight="0"        android:background="@color/bottomTabBarColor">        <FrameLayout            android:id="@+id/fl_tab_wrap"            android:layout_width="wrap_content"            android:layout_height="wrap_content"/>    </android.support.v4.app.FragmentTabHost>

代码初始化tabhost

private void initTabHost() {        layoutInflater = LayoutInflater.from(this);        mTabHost = (FragmentTabHost)findViewById(android.R.id.tabhost);        mTabHost.setup(this, getSupportFragmentManager(), R.id.fl_home_content);        int count = mFragmentArray.length;        for(int i = 0; i < count; i++){            TabHost.TabSpec tabSpec = mTabHost.newTabSpec(context.getString(mTextviewArray[i])).setIndicator(getTabItemView(i));            mTabHost.addTab(tabSpec, mFragmentArray[i], null);            mTabHost.getTabWidget().setShowDividers((LinearLayout.SHOW_DIVIDER_NONE));        }    }    private View getTabItemView(int index){        View view = layoutInflater.inflate(R.layout.home_tab_item, null);        ImageView imageView = (ImageView) view.findViewById(R.id.iv_tab_icon);       imageView.setImageResource(mImageViewArray[index]);        return view;    }

如果，当某个fragment中切换其他fragment（不是tab对应的mFragmentArray中），返回就会crash。原因是什么？

3，对话框问题

<!--自定义对话框-->    <style name="dialog1" parent="@android:style/Theme.Dialog">        <item name="android:windowFrame">@null</item><!--边框-->        <item name="android:windowIsFloating">true</item><!--是否浮现在activity之上-->        <item name="android:windowIsTranslucent">true</item><!--半透明-->        <item name="android:windowNoTitle">true</item><!--无标题-->        <item name="android:windowBackground">@android:color/darker_gray</item><!--背景透明-->        <item name="android:backgroundDimEnabled">true</item><!--背景变暗-->    </style>

 public void showCommonDialog(final OnDialogBtnClickListener onDialogBtnClickListener) {        final Dialog dialog = new Dialog(context, R.style.dialog1);//自定义布局文件     dialog.setContentView(R.layout.dialog_common_hint);        dialog.setCancelable(true);        btn_left = (Button) dialog.findViewById(R.id.btn_positive);        btnRight = (Button) dialog.findViewById(R.id.btn_negative);        TextView tv_description = (TextView)dialog.findViewById(R.id.tv_dialog_description);        tv_description.setText(description);        //左侧        btn_left.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                onDialogBtnClickListener.onPositiveClick(v);                dialog.dismiss();            }        });        //右侧        btnRight.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                onDialogBtnClickListener.onNegativeClick(v);                dialog.dismiss();            }        });        dialog.show();    }

dialog对应的布局，添加一个圆角背景

<?xml version="1.0" encoding="utf-8"?><shape  xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="rectangle">    <corners android:radius="10dp" />    <solid android:color="@color/common_bg" /></shape>

4，水平进度条

1、新建 myprogress_style.xml在drawable中

android:startColor=”@color/red” 为自定义开始颜色
为两头圆角的弧度，值越大越圆
为设置渐变色背景 angle 为角度

<?xml version="1.0" encoding="UTF-8"?><layer-list xmlns:android="http://schemas.android.com/apk/res/android"><item android:id="@android:id/background">    <shape>    <corners android:radius="8.0dip" />    <gradient android:startColor="#EEEEEE" android:endColor="#EEEEEE"    android:angle="270.0" />    </shape></item><item android:id="@android:id/progress">    <clip>    <shape>        <corners android:radius="0.0dip" />        <gradient android:startColor="@color/red" android:endColor="@color/red"        android:centerColor="@color/red" android:angle="270.0" />    </shape>    </clip></item></layer-list>

2、应用样式

<ProgressBar android:id="@+id/pic_ProgressBar"style="?android:attr/progressBarStyleHorizontal" android:layout_width="fill_parent" android:visibility="gone" android:layout_height="5dip"android:progressDrawable="@drawable/myprogress_style">

5，splash首屏加载黑屏问题

//设置透明Theme，防止黑白屏，进入app闪烁

<style name="Theme.AppTranslucent" parent="android:Theme">      <item name="android:windowIsTranslucent">true</item>     <item name="android:windowNoTitle">true</item>  </style>

6，物理后退模拟点击Home键

后退，直接返回桌面，并不退出应用。

@Overridepublic void onBackPressed() {    //super.onBackPressed();这句话要注掉,否则又去调用默认的back处理方式了    Intent mIntent = new Intent();    mIntent.setAction(Intent.ACTION_MAIN);    mIntent.addCategory(Intent.CATEGORY_HOME);    startActivity(mIntent);}

7，根据android文件ID，查找缩略图

视频缩略图类似，通过多媒体数据库获取。

 private Bitmap getImageThumbBitmap(int ImageID, String path) {        Bitmap bitmap = null;        if (ImageID!=-1&&ImageID>0) {            bitmap = MediaStore.Images.Thumbnails.getThumbnail(                    contentResolver, ImageID, MediaStore.Images.Thumbnails.MINI_KIND, null);        }        if (bitmap == null){            bitmap = MyFileUtils.getImageThumbnail(path, 80, 80);        }        return bitmap;    }

8，string.xml中不能有特殊符号

项目中要在string.xml 中显示特殊符号，如@号冒号等，直接写肯定不行啦。使用ASCII码进行显示。如：

@号 &#064; :号 &#058; 空格 &#160;

9，Android自定义通知栏

public void createNotification() {        String title = context.getString(R.string.notify_downloading_title)+fileName;        notification = new Notification(                R.mipmap.ic_launcher,//应用的图标                title,                System.currentTimeMillis());        notification.tickerText = title;        //notification.flags = Notification.FLAG_ONGOING_EVENT;        notification.flags = Notification.FLAG_AUTO_CANCEL;        contentView = new RemoteViews(context.getPackageName(),R.layout.notification_item);        contentView.setTextViewText(R.id.notificationTitle, title);        contentView.setTextViewText(R.id.notificationPercent, "0%");        contentView.setProgressBar(R.id.notificationProgress, 100, 0, false);        notification.contentView = contentView;        //点击后进入缓存列表        downloadIntent = new Intent(context, HomeActivity.class);        downloadIntent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);        pendingIntent = PendingIntent.getActivity(context, 0, downloadIntent, 0);        notification.contentIntent = pendingIntent;        notificationManager = NotificationUtils.getManager(context);    }

10，Android常用工具，其他相关

IDE：android studio，eclipse
文本编辑器：Sublmine，Atom
版本控制：svn，git
笔记：为知笔记，有道云笔记，万象笔记
开发者学习常用站点：github，csdn，简书，掘金，推酷，慕课网
android大牛：一大堆，希望有你。

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