ImageView实现图片旋转和缩放功能

在开发中实现对图像的缩放有很多方法，最简单的方法是改变ImageView控件的大小，我们只要将<ImageView>标签的android:scaleType的属性值设置为fitCenter,要是想实现图像的旋转可以使用android.graphics.Matirx类的setRotate来实现。

下面介绍，图片的旋转和缩放功能。

一、建立工程，如图

package com.study.rotateimageview;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.util.DisplayMetrics;
import android.view.Menu;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.SeekBar.OnSeekBarChangeListener;

public class MainActivity extends Activity implements OnSeekBarChangeListener{

private int minWidth = 80;
private ImageView imageView;
private TextView textView1,textView2;
private Matrix matrix = new Matrix();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

imageView = (ImageView)this.findViewById(R.id.imageview);
SeekBar seekBar1 = (SeekBar)this.findViewById(R.id.seekbar1);
SeekBar seekBar2 = (SeekBar)this.findViewById(R.id.seekbar2);
textView1 = (TextView)this.findViewById(R.id.textview1);
textView2 = (TextView)this.findViewById(R.id.textview2);
seekBar1.setOnSeekBarChangeListener(this);
seekBar2.setOnSeekBarChangeListener(this);
//
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
seekBar1.setMax(dm.widthPixels - minWidth);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
if(seekBar.getId() == R.id.seekbar1){
int newWidth = progress + minWidth;
int newHeight = (int)(newWidth*3/4);//按照原比例缩放
imageView.setLayoutParams(new LinearLayout.LayoutParams(newWidth, newHeight));
textView1.setText("图像宽度:" + newWidth + "  图像高度:" + newHeight);
}else if(seekBar.getId() == R.id.seekbar2){
Bitmap bitmap = ((BitmapDrawable)(getResources().getDrawable(R.drawable.background))).getBitmap();
matrix.setRotate(progress);
bitmap = Bitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);
imageView.setImageBitmap(bitmap);
textView2.setText(progress + "度");
}
}

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

}

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

}

}

View Code
四、效果图



缩放：



旋转：