TextView及其子类

本文总结TextView及其子类的一些用法和性质

1、用TextView设置滚动文本，获取宽度及字数

1）创建一个继承TextView的类，覆写isFocused方法。在XML文件给TextView增加ellipsize="marquee"的属性

public class MarqueeTextView extends TextView {public MarqueeTextView(Context context) {super(context);}public MarqueeTextView(Context context,AttributeSet as){super(context, as);}public MarqueeTextView(Context context,AttributeSet as,int defStyle){super(context, as, defStyle);}@Override@ExportedProperty(category = "focus")public boolean isFocused() {return true;}}

<com.me.spinner.MarqueeTextView         android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:singleLine="true"        android:text="0123456789-0123456789-0123456789-0123456789-0123456789-0123456789-0123456789"        android:ellipsize="marquee"        android:focusable="true"        android:focusableInTouchMode="true"        android:scrollHorizontally="true"        android:marqueeRepeatLimit="marquee_forever"        android:background="@android:color/transparent"/>

2）获取字符长度，区分普通字符和汉字

private int getCharLength(String str){    if(TextUtils.isEmpty(str)){        return 0;    }    int len=0;    for(int i=0;i<str.length();i++){        Character.UnicodeBlock ub = Character.UnicodeBlock.of(str.charAt(i));        if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS                || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS                || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A                || ub == Character.UnicodeBlock.GENERAL_PUNCTUATION                || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION                || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS) {            len += 2;        }else{            len += 1;        }    }    return len;}private String getShortChars(String str){    if(TextUtils.isEmpty(str)){        return str;    }    int len=0;    for(int i=0;i<str.length();i++){        Character.UnicodeBlock ub = Character.UnicodeBlock.of(str.charAt(i));        //汉字取2普通字符取1        if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS                || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS                || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A                || ub == Character.UnicodeBlock.GENERAL_PUNCTUATION                || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION                || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS) {            len += 2;        }else{            len += 1;        }        if(len>3){            return str.substring(0, i);        }    }    return str;}

还有些方法参考：getBytes(), length(), textView.getPaint().measureText(""), 

getMeasuredWidth(), getWidth(), getTextSize()等

TextView字数过长默认截断并末尾显示"..."，设置android:ellipsize="none"会取消省略号，默认值为“end”

2、一些按钮实现

1）示例代码

public class MainActivity extends Activity {private static final String TAG = MainActivity.class.getSimpleName();@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//TextView子类Button button = (Button) findViewById(R.id.v_button);button.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Log.println(Log.VERBOSE, TAG, "Button");}});//ImageView子类ImageButton imageButton = (ImageButton) findViewById(R.id.imageButton);imageButton.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Log.println(Log.DEBUG, TAG, "ImageButton");}});//CompoundButton(extends Button implements Checkable)子类Switch mSwitch = (Switch) findViewById(R.id.v_switch);mSwitch.setOnCheckedChangeListener(new OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {if(isChecked){Log.println(Log.INFO, TAG, "已打开");}else{Log.println(Log.INFO, TAG, "已关闭");}}});ToggleButton toggleButton = (ToggleButton) findViewById(R.id.v_togglebutton);toggleButton.setOnCheckedChangeListener(new OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {if(isChecked){Log.w(TAG, "已打开");//Log.WARN}else{Log.w(TAG, "已关闭");}}});CheckBox checkBox = (CheckBox) findViewById(R.id.checkBox);checkBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {if(isChecked){Log.e(TAG, "已打开");//Log.ERROR}else{Log.e(TAG, "已关闭");}}});RadioGroup radioGroup = (RadioGroup) findViewById(R.id.radioGroup);radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(RadioGroup group, int checkedId) {switch (checkedId) {case R.id.radioButton1:Log.wtf(TAG, "radioButton1");//Log.ASSERTbreak;case R.id.radioButton2:Log.wtf(TAG, "radioButton2");}}});}}

<?xml version="1.0" encoding="utf-8"?><LinearLayout    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    xmlns:android="http://schemas.android.com/apk/res/android">    <Button         android:id="@+id/v_button"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Button"/>    <ImageButton         android:id="@+id/imageButton"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:src="@drawable/ic_launcher"/>    <Switch         android:id="@+id/v_switch"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Switch"        android:textOn="On"        android:textOff="Off"/>    <ToggleButton         android:id="@+id/v_togglebutton"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textOn="On"        android:textOff="Off"/>    <CheckBox         android:id="@+id/checkBox"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="CheckBox"/>    <RadioGroup         android:id="@+id/radioGroup"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:orientation="horizontal">        <RadioButton         android:id="@+id/radioButton1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="RadioButton1"/>        <RadioButton         android:id="@+id/radioButton2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="RadioButton2"/>    </RadioGroup></LinearLayout>

2）分析

Button继承自TextView，继承了其android:text="Button"属性。

ImageButton继承自ImageView，继承了其android:src="@drawable/ic_launcher"属性。

Switch、ToggleButton、CheckBox、RadioButton继承自CompoundButton，通过设置CompoundButton.OnCheckedChangeListener来监听check状态。

CompoundButton继承Button类、实现Checkable接口，是不含抽象方法的抽象类。

RadioButton配合RadioGroup使用。RadioGroup设置RadioGroup.OnCheckedChangeListener来监听单选按钮选择状态的变化。

3、一些小技巧

1）给EditText设置错误提示

/*Sets the right-hand compound drawable of the TextView to the "error" icon and sets an error message that will be displayed in a popup when the TextView has focus*/editText.setError("尖叫");

2）将TextView文本变成可跳转的链接

<TextView     android:layout_width="match_parent"    android:layout_height="wrap_content"    android:autoLink="web"    android:text="http://www.baidu.com"/>

4、android圆角按钮的设置

1)首先在res/drawable目录下创建selector_rectangle.xml文件,在其中设置圆角的半径及背景色:

<selector xmlns:android="http://schemas.android.com/apk/res/android">    <item android:state_pressed="true">        <shape android:shape="rectangle">    <gradient         android:startColor="@android:color/white"        android:endColor="@android:color/black"        android:type="linear"        android:angle="0"/>    <stroke         android:width="1px"        android:color="@android:color/black"/>            <solid android:color="@color/yellow"/>            <corners android:radius="4dp"/>        </shape>    </item>    <item >        <shape android:shape="rectangle">    <solid android:color="@color/white"/>    <corners android:radius="4dip"/></shape>    </item></selector>

其中item标签的state_pressed属性用于区分是否摁下，gradient设置背景色为渐变色，stroke设置边框。

2)然后在布局文件的Button标签background属性设置此selector:

<Buttonandroid:layout_width="0dp"android:layout_height="wrap_content"android:text="@string/knowledge_btn_cp"android:drawableTop="@drawable/knowledge_cp"android:background="@drawable/selector_rectangle"android:onClick="onClick"/>

5、自定义TextView

1、定义一个继承TextView的类

public class MyTextView extends TextView {private Paint marginPaint;private Paint linePaint;private int paperColor;private float margin;public MyTextView(Context context){this(context, null);}public MyTextView(Context context,AttributeSet as){//系统调用此构造器this(context, as, android.R.attr.textViewStyle);}public MyTextView(Context context,AttributeSet as,int defStyle){super(context, as, defStyle);init();}@Overrideprotected void onDraw(Canvas canvas) {//绘制背景canvas.drawColor(paperColor);//绘制左边线canvas.drawLine(0, 0, 0, getMeasuredHeight(), linePaint);//绘制底线canvas.drawLine(0, getMeasuredHeight(), getMeasuredWidth(), getMeasuredHeight(), linePaint);//绘制中间竖线canvas.drawLine(margin, 0, margin, getMeasuredHeight(), marginPaint);canvas.save();canvas.translate(margin, 0);super.onDraw(canvas);//平移后绘制文字canvas.restore();}private void init(){Resources resources = getResources();marginPaint = new Paint(Paint.ANTI_ALIAS_FLAG);marginPaint.setColor(resources.getColor(R.color.notepad_margin));//#90ff0000linePaint = new Paint(Paint.ANTI_ALIAS_FLAG);linePaint.setColor(resources.getColor(R.color.notepad_lines));//#ff0000ffpaperColor = resources.getColor(R.color.notepad_paper);//#eef8e0a0margin = resources.getDimension(R.dimen.notepad_margin);}}

colors.xml

<?xml version="1.0" encoding="utf-8"?><resources>    <color name="notepad_paper">#eef8e0a0</color><!-- R.color.notepad_paper -->    <color name="notepad_lines">#ff0000ff</color>    <color name="notepad_margin">#90ff0000</color>    <color name="notepad_text">#aa0000ff</color></resources>

dimens.xml

<?xml version="1.0" encoding="utf-8"?><resources>    <dimen name="notepad_margin">30dp</dimen></resources>

2、定义ListActivity的子类及布局文件

public class MainActivity extends ListActivity {TextView tv;private static final String TAG = "info";@Overrideprotected void onCreate(Bundle savedInstanceState) {Log.d(TAG, "onCreate");super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);String[] colors = {"red","green","blue","yellow","gray","black","white","purple","orange","brown",};//实例化10个TextViewListAdapter mListAdapter = new ArrayAdapter<String>(this, R.layout.todolist_item, colors);//参数指定item样式和datasetListAdapter(mListAdapter);}}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout     android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    xmlns:android="http://schemas.android.com/apk/res/android">    <TextView         android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center"        android:text="五颜六色"        android:textColor="#ffffffff"        android:background="#88880000"/>    <ListView    android:id="@android:id/list"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:layout_margin="10dp"/></LinearLayout>

todolist_item.xml

<?xml version="1.0" encoding="utf-8"?><!-- 设置文本颜色 --><com.qinuli.textviewtest.MyTextView    xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/myTextView"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:padding="10dp"    android:scrollbars="vertical"    android:textColor="@color/notepad_text"    android:fadingEdge="vertical"/>