Android----imageView实现图片的旋转和缩放

import android.support.v7.app.ActionBarActivity;
import android.util.DisplayMetrics;
import android.annotation.SuppressLint;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.SeekBar.OnSeekBarChangeListener;

@SuppressLint ( "NewApi" )
public class MainActivity extends ActionBarActivity implements OnSeekBarChangeListener{
    //最小的缩放宽度
    private int minWidth = 80 ;
    private ImageView imageView;
    private SeekBar seekBar1;
    private SeekBar seekBar2;
    private TextView textView1;
    private TextView textView2;
    //矩阵类,用于对图像进行旋转
    private Matrix matrix = new Matrix();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super .onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView = (ImageView)findViewById(R.id.imageView);
        seekBar1 = (SeekBar)findViewById(R.id.seekBar1);
        seekBar2 = (SeekBar)findViewById(R.id.seekBar2);
        seekBar1.setOnSeekBarChangeListener( this );
        seekBar2.setOnSeekBarChangeListener( this );
        textView1 = (TextView)findViewById(R.id.textview1);
        textView2 = (TextView)findViewById(R.id.textview2);
        //创建一个空的展示矩阵，用于存储当前屏幕信息，如大小。
        DisplayMetrics displayMetrics = new DisplayMetrics();
        //把当前管理的屏幕尺寸传递给displayMetrics
        getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
        //设置放大的最大值不超过屏幕大小
        seekBar1.setMax(displayMetrics.widthPixels-minWidth);
    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,
            boolean fromUser) {
        if (seekBar.getId()==R.id.seekBar1) {
            //设置宽度为80到最大
            int mwidth = progress+minWidth;
            int mheight = ( int )( 2 *mwidth/ 3 );
            //设置imageView的输出大小参数
            //因为图片是fitcenter参数，所以图片会随着image框架的大小变化而变化
            //从而改变image框架的大小会引起图片大小的变化，实现图片的放大缩小功能
            imageView.setLayoutParams( new LinearLayout.LayoutParams(mwidth, mheight));
            textView1.setText( "图片宽度：" +mwidth+ "\t图片高度：" +mheight);
        } else if (seekBar.getId()==R.id.seekBar2) {
            //imageView自身的setRotation方法是绕图的中心顺时针防线旋转
            //同时该旋转不会改变imageView的输出大小，所超出imageView的部分会照常显示在所跨越视图的下方
            //imageView.setRotation(progress);

            //如果想创建一个不超出imageView输出框架的旋转图像，那么需要把原图像取出，把原图像进行旋转，重新放入到imageView 中
            //缺陷：占用系统较多的内存，会比较卡
            Bitmap bitmap = ((BitmapDrawable)(getResources().getDrawable(R.drawable.photo))).getBitmap();
            matrix.setRotate(progress);
            bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
            imageView.setImageBitmap(bitmap);
            textView2.setText("图片旋转"+progress+"度");
        }

    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }
}

"http://schemas.android.com/apk/res/android"

android:layout_width= "fill_parent"
android:layout_height= "fill_parent"
android:orientation= "vertical" >

android:id= "@+id/imageView"
android:layout_width= "300dp"
android:layout_height= "200dp"
android:scaletype= "fitCenter"
android:src= "@drawable/photo"/ >

android:id= "@+id/textview1"
android:layout_width= "wrap_content"
android:layout_height= "wrap_content"
android:text= "图片缩放"/ >

android:id= "@+id/seekBar1"
android:layout_width= "match_parent"
android:layout_height= "wrap_content"
android:max= "480"
android:progress= "300"/ >

android:id= "@+id/textview2"
android:layout_width= "wrap_content"
android:layout_height= "wrap_content"
android:text= "图片旋转"/ >

android:id= "@+id/seekBar2"
android:layout_width= "match_parent"
android:layout_height= "wrap_content"
android:max= "360"
android:progress= "0"/ >