Android中imageView图片放大缩小及旋转功能示例代码

android:scaleType="fitCenter"

DisplayMetrics dm=new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(dm);dm.widthPixels

sb_one.setMax(dm.widthPixels);

int width=progress;int height=progress*3/4;iv_pic.setLayoutParams(new LinearLayout.LayoutParams(width, height));

private Matrix matrix;matrix.setRotate((int)(progress*3.60));

BitmapDrawable bitmapDrawable=(BitmapDrawable)(getResources().getDrawable(R.drawable.image1));Bitmap bitmap=bitmapDrawable.getBitmap();

Bitmap newBitmap=bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(),matrix,false);

iv_pic.setImageBitmap(newBitmap);

package fry;import com.example.iamgeViewDemo1.R;import android.app.Activity;import android.graphics.Bitmap;import android.graphics.Matrix;import android.graphics.drawable.BitmapDrawable;import android.os.Bundle;import android.util.DisplayMetrics;import android.view.ViewGroup.LayoutParams;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.SeekBar;import android.widget.SeekBar.OnSeekBarChangeListener;public class Activity02 extends Activity implements OnSeekBarChangeListener{  private ImageView iv_pic;  private SeekBar sb_one;  private SeekBar sb_two;  private Matrix matrix;  @Override  protected void onCreate(Bundle savedInstanceState) {    // TODO Auto-generated method stub    setTitle("imageView实现图片缩放和旋转");    super.onCreate(savedInstanceState);    setContentView(R.layout.activity02);    iv_pic=(ImageView) findViewById(R.id.iv_pic);    sb_one=(SeekBar) findViewById(R.id.sb_one);    sb_two=(SeekBar) findViewById(R.id.sb_two);    //设置SeekBar的progress值改变监听事件    sb_one.setOnSeekBarChangeListener(this);    sb_two.setOnSeekBarChangeListener(this);    matrix=new Matrix();//    1）设置图片放大缩小效果////    第一步：将<ImageView>标签中的android:scaleType设置为"fitCenter"////    第二步：获取屏幕的宽度////    第三步：设置seekBar的最大progree值为屏幕宽度////    第四步：设置imageview的布局参数，也就是宽和高，也就是画布的宽高    //设置图片放大缩小效果    //第一步：获取屏幕的宽度    DisplayMetrics dm=new DisplayMetrics();    getWindowManager().getDefaultDisplay().getMetrics(dm);    //第二步：设置seekBar的最大progree值为屏幕宽度    sb_one.setMax(dm.widthPixels);  }  @Override  public void onProgressChanged(SeekBar seekBar, int progress,      boolean fromUser) {    // TODO Auto-generated method stub    switch (seekBar.getId()) {    case R.id.sb_one://放大或缩小      int width=progress;      int height=progress*3/4;      //第三步：设置imageview的布局参数，也就是宽和高，也就是画布的宽高      iv_pic.setLayoutParams(new LinearLayout.LayoutParams(width, height));      break;    case R.id.sb_two://旋转      //设置旋转度数      //设置图片旋转方法      //第一步：给matrix设置角度，用于新的bitmap      matrix.setRotate((int)(progress*3.60));      //第二步：获取bitmap资源      BitmapDrawable bitmapDrawable=(BitmapDrawable)(getResources().getDrawable(R.drawable.image1));      Bitmap bitmap=bitmapDrawable.getBitmap();      //第三步：重建bitmap用于显示      Bitmap newBitmap=bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(),matrix,false);      //第四步：给imageview设置新的bitmap      iv_pic.setImageBitmap(newBitmap);      break;    default:      break;    }  }  @Override  public void onStartTrackingTouch(SeekBar seekBar) {    // TODO Auto-generated method stub  }  @Override  public void onStopTrackingTouch(SeekBar seekBar) {    // TODO Auto-generated method stub  }}

<?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" >  <ImageView     android:id="@+id/iv_pic"    android:layout_width="match_parent"    android:layout_height="300dip"    android:background="@android:color/black"    android:scaleType="fitCenter"    android:src="@drawable/image1"    />  <!-- 设置图片的显示方式：把图片按比例扩大/缩小到view的宽度，居中显示 -->  <SeekBar    android:id="@+id/sb_one"    android:layout_width="match_parent"    android:layout_height="wrap_content"     android:progress="100"    />  <TextView     android:layout_width="match_parent"    android:layout_height="wrap_content"    android:text="拖动来缩放图片"    />  <SeekBar     android:id="@+id/sb_two"    android:layout_width="match_parent"    android:layout_height="wrap_content"    />  <TextView     android:layout_width="match_parent"    android:layout_height="wrap_content"    android:text="拖动来旋转图片"    /></LinearLayout>

android:scaleType="fitCenter"