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

二、activity_main.xml中代码

<?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">
    
    <ImageView android:id="@+id/imageview" 
        android:layout_width="200dp"
        android:layout_height="150dp"
        android:src="@drawable/background"
        android:scaleType="fitCenter"
        >
        
    </ImageView>
    <TextView 
        android:id="@+id/textview1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="图像宽度：240 图像高度：160"
        />
    <SeekBar 
        android:id="@+id/seekbar1"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:max="240"
        android:progress="120"
        />
    <TextView 
        android:id="@+id/textview2"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="0度"
        />
      <SeekBar 
        android:id="@+id/seekbar2"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:max="360"
        />
    
</LinearLayout>

三、MainActivity.java中代码

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
        
    }
    
}

四、效果图

缩放：

旋转：