縮放系列（二）：所有子控件也隨着縮放、手勢縮放、多點觸控layout

下面是一個功能強大的改造的例子：

可以實現以下需求：

1.兩個手指進行縮放布局

2.所有子控件也隨着縮放，

3.子控件該有的功能不能丟失（像button有可被點擊的功能，縮放后不能丟失該功能）

 運行效果圖：

 

java代碼如下

MainActivity.java:

public class MainActivity extends ActionBarActivity {
    private ScaleGestureDetector mScaleGestureDetector = null;
    private View view;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // setContentView(R.layout.test);
        view = View.inflate(this, R.layout.activity_main, null);
        setContentView(view);
        
        mScaleGestureDetector = new ScaleGestureDetector(this,
                new ScaleGestureListener());


    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // 返回給ScaleGestureDetector來處理
        return mScaleGestureDetector.onTouchEvent(event);
    }

    public class ScaleGestureListener implements
            ScaleGestureDetector.OnScaleGestureListener {

        private float scale;
        private float preScale = 1;// 默認前一次縮放比例為1

        @Override
        public boolean onScale(ScaleGestureDetector detector) {

            float previousSpan = detector.getPreviousSpan();
            float currentSpan = detector.getCurrentSpan();
            if (currentSpan < previousSpan) {
                // 縮小
                // scale = preScale-detector.getScaleFactor()/3;
                scale = preScale - (previousSpan - currentSpan) / 1000;
            } else {
                // 放大
                // scale = preScale+detector.getScaleFactor()/3;
                scale = preScale + (currentSpan - previousSpan) / 1000;
            }

            // 縮放view
            ViewHelper.setScaleX(view, scale );// x方向上縮小
            ViewHelper.setScaleY(view, scale );// y方向上縮小

            return false;
        }

        @Override
        public boolean onScaleBegin(ScaleGestureDetector detector) {
            // 一定要返回true才會進入onScale()這個函數
            return true;
        }

        @Override
        public void onScaleEnd(ScaleGestureDetector detector) {
            preScale = scale;//記錄本次縮放比例
        }
    }
}

布局文件(activity_main.xml)：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" 
    android:background="@drawable/home_tools"
    >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="測試" />

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/abc_ic_voice_search_api_holo_light" />

    <ImageButton
        android:id="@+id/imageButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/selector_button2" />

    <ImageButton
        android:id="@+id/imageButton2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/selector_button1" 
        android:layout_gravity="center"
        />

</LinearLayout>

 selector_button1.xml：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
    <item android:drawable="@drawable/home_tools" android:state_pressed="true"></item>
    <item android:drawable="@drawable/home_trojan"></item>
</selector>

selector_button2.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
    <item android:drawable="@drawable/home_sysoptimize" android:state_pressed="true"></item>
    <item android:drawable="@drawable/home_taskmanager"></item>
</selector>

  

如果想要整個布局能夠移動，可以看下面的帖子：

 http://www.cnblogs.com/johnsonwei/p/5831925.html