Android(安卓)Launcher研究(四)-----------桌面应用快捷方式的开发!

大家好，今天我给大家分享的是Launcher桌面快捷图标的开发，我们都知道快捷图标有两部分组成，一部分是应用的图标，另一部分就是应用的名称。其实Launcher中的快捷图标只是继承了TextView控件，重绘了一下，将背景弄成浅灰色(具体是什么颜色我也不知道）的椭圆背景，显示的文字颜色则是白色。TextView有android:drawableTop;drawableBottom(上下左右我这里就不全写出来了)属性，用来显示应用的图标。

废话不多说了，直接上例子，大家一步一步来，多敲敲代码，成长快一点。

第一步：新建一个Android工程，命名为ApplicationDemo.如下图:

第二步:在values目录下新建colors.xml文件，定义一些要用的颜色，代码如下:

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<?xmlversion= "1.0" encoding= "utf-8" ?>
<resources>
<colorname="white" >#FFFFFF</color>
<colorname="black" ># 000000 </color>
<colorname="bubble_dark_background" >#B2191919</color>
</resources>

<?xml version="1.0" encoding="utf-8"?><resources> <color name="white">#FFFFFF</color> <color name="black">#000000</color> <color name="bubble_dark_background">#B2191919</color></resources>

第三步：也就是重点了，新建一个BubbleTextView类，继承TextView,代码如下:

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package com.tutor.application;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.text.Layout;
import android.util.AttributeSet;
import android.widget.TextView;
public class BubbleTextView extends TextView{
private static final int CORNER_RADIUS= 8 ;
private static final int PADDING_H= 5 ;
private static final int PADDING_V= 1 ;
private final RectFmRect= new RectF();
private PaintmPaint;
public BubbleTextView(Contextcontext){
super (context);
init();
}
public BubbleTextView(Contextcontext,AttributeSetattrs){
super (context,attrs);
init();
}
public BubbleTextView(Contextcontext,AttributeSetattrs, int defStyle){
super (context,attrs,defStyle);
init();
}
private void init(){
setFocusable(true );
//Weneedextrapaddingbelowtopreventthebubblebeingcut.
setPadding(PADDING_H,0 ,PADDING_H,PADDING_V);
mPaint=new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setColor(getContext().getResources()
.getColor(R.color.bubble_dark_background));
}
@Override
protected void drawableStateChanged(){
invalidate();
super .drawableStateChanged();
}
@Override
public void draw(Canvascanvas){
final Layoutlayout=getLayout();
final RectFrect=mRect;
final int left=getCompoundPaddingLeft();
final int top=getExtendedPaddingTop();
rect.set(left+layout.getLineLeft(0 )-PADDING_H,
top+layout.getLineTop(0 )-PADDING_V,
Math.min(left+layout.getLineRight(0 )+PADDING_H,
getScrollX()+getRight()-getLeft()),
top+layout.getLineBottom(0 )+PADDING_V);
canvas.drawRoundRect(rect,CORNER_RADIUS,CORNER_RADIUS,mPaint);
super .draw(canvas);
}
}

package com.tutor.application;import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.RectF;import android.text.Layout;import android.util.AttributeSet;import android.widget.TextView;public class BubbleTextView extends TextView { private static final int CORNER_RADIUS = 8; private static final int PADDING_H = 5; private static final int PADDING_V = 1; private final RectF mRect = new RectF(); private Paint mPaint; public BubbleTextView(Context context) { super(context); init(); } public BubbleTextView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public BubbleTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } private void init() { setFocusable(true); // We need extra padding below to prevent the bubble being cut. setPadding(PADDING_H, 0, PADDING_H, PADDING_V); mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mPaint.setColor(getContext().getResources() .getColor(R.color.bubble_dark_background)); } @Override protected void drawableStateChanged() { invalidate(); super.drawableStateChanged(); } @Override public void draw(Canvas canvas) { final Layout layout = getLayout(); final RectF rect = mRect; final int left = getCompoundPaddingLeft(); final int top = getExtendedPaddingTop(); rect.set(left + layout.getLineLeft(0) - PADDING_H, top + layout.getLineTop(0) - PADDING_V, Math.min(left + layout.getLineRight(0) + PADDING_H, getScrollX() + getRight() - getLeft()), top + layout.getLineBottom(0) + PADDING_V); canvas.drawRoundRect(rect, CORNER_RADIUS, CORNER_RADIUS, mPaint); super.draw(canvas); }}

第四步:修改main.xml布局文件，代码如下:

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<?xmlversion= "1.0" encoding= "utf-8" ?>
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:drawableTop="@drawable/icon"
android:text="ApplicationDemo"
android:textColor="@color/black"
/>
<com.tutor.application.BubbleTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:drawableTop="@drawable/icon"
android:textColor="@color/white"
android:text="ApplicationDemo"
/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" ><TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:drawableTop="@drawable/icon" android:text="ApplicationDemo" android:textColor="@color/black" /><com.tutor.application.BubbleTextViewandroid:layout_width="wrap_content" android:layout_height="wrap_content" android:drawableTop="@drawable/icon" android:textColor="@color/white" android:text="ApplicationDemo"/></LinearLayout>

第五步:修改AndroidManifest.xml文件，注意这里我们在Activity里增加了一个透明的样式，Launcher其实就是透明的Activity。

代码如下(第8行代码):

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<?xmlversion= "1.0" encoding= "utf-8" ?>
<manifestxmlns:android="http://schemas.android.com/apk/res/android"
package = "com.tutor.application"
android:versionCode="1"
android:versionName="1.0" >
<applicationandroid:icon="@drawable/icon" android:label= "@string/app_name" >
<activityandroid:name=".ApplicationDemo"
android:theme="@android:style/Theme.Wallpaper.NoTitleBar"
android:label="@string/app_name" >
<intent-filter>
<actionandroid:name="android.intent.action.MAIN" />
<categoryandroid:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-sdkandroid:minSdkVersion="7" />
</manifest>

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.tutor.application" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".ApplicationDemo" android:theme="@android:style/Theme.Wallpaper.NoTitleBar" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> <uses-sdk android:minSdkVersion="7" /></manifest>

第六步:运行上述工程，查看效果如下:

将android:drawableLeft修改为android:drawableTop，效果如下:

Ok~大功告成，收工睡觉!!!

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