Android开发_拖动效果，旋转效果，两点放大缩小的实现

[java]

最近在做一个项目，需要用到拖动图片，旋转效果，两点放大缩小。

首先拖动图片

布局，主要就是一个button做测试

[html]
<?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="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
    <Button
    android:id="@+id/btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/bt"
    />
</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="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
    <Button
    android:id="@+id/btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/bt"
    />
</LinearLayout>

[java]
package com.oppo.examples;

import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.Toast;

public class DraftTest extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        DisplayMetrics dm = getResources().getDisplayMetrics();
        final int screenWidth = dm.widthPixels;
        final int screenHeight = dm.heightPixels - 50;

        final Button b=(Button)findViewById(R.id.btn);

        b.setOnTouchListener(new OnTouchListener(){

            int lastX, lastY;

            @Override
            public boolean onTouch(View v, MotionEvent event) {
                // TODO Auto-generated method stub
                int ea=event.getAction();
                Log.i("TAG", "Touch:"+ea);

                //Toast.makeText(DraftTest.this, "位置："+x+","+y, Toast.LENGTH_SHORT).show();

                switch(ea){
                case MotionEvent.ACTION_DOWN:
                    lastX = (int) event.getRawX();
                    lastY = (int) event.getRawY();
                    break;
                    /**
                     * layout(l,t,r,b)
                     * l Left position, relative to parent
                    t Top position, relative to parent
                    r Right position, relative to parent
                    b Bottom position, relative to parent
                     * */
                case MotionEvent.ACTION_MOVE:
                    int dx =(int)event.getRawX() - lastX;
                    int dy =(int)event.getRawY() - lastY;

                    int left = v.getLeft() + dx;
                    int top = v.getTop() + dy;
                    int right = v.getRight() + dx;
                    int bottom = v.getBottom() + dy;

补充：移动开发 , Android ,