Android（java）学习笔记240：多媒体之图形颜色的变化

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.himi.xiuxiu.MainActivity" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="青------------->红" />

<SeekBar
android:id="@+id/sb_red"
android:max="255"
android:progress="128"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="紫------------->绿" />

<SeekBar
android:max="255"
android:progress="128"
android:id="@+id/sb_green"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="黄------------->蓝" />

<SeekBar
android:max="255"
android:progress="128"
android:id="@+id/sb_blue"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/iv"
/>

</LinearLayout>

 package com.himi.xiuxiu;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;

public class MainActivity extends Activity implements OnSeekBarChangeListener {
private SeekBar sb_red;
private SeekBar sb_green;
private SeekBar sb_blue;
private ImageView iv;

private Bitmap srcbitmap;
private Bitmap alertbitmap;
private Canvas canvas;
private Paint paint;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sb_red = (SeekBar) findViewById(R.id.sb_red);
sb_green = (SeekBar) findViewById(R.id.sb_green);
sb_blue = (SeekBar) findViewById(R.id.sb_blue);
iv = (ImageView) findViewById(R.id.iv);
//获得原图的位图
srcbitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pre19);
//获得原图的拷贝副本
alertbitmap = Bitmap.createBitmap(srcbitmap.getWidth(), srcbitmap.getHeight(), srcbitmap.getConfig());
//创建一个画布
canvas = new Canvas(alertbitmap);
//创建画笔
paint = new Paint();

ColorMatrix cm = new ColorMatrix();
cm.set(new float[] {
1, 0, 0, 0, 0,
0, 1, 0, 0, 0,
0, 0, 1, 0, 0,
0, 0, 0, 1, 0
});

paint.setColorFilter(new ColorMatrixColorFilter(cm));
canvas.drawBitmap(srcbitmap, new Matrix(), paint);
iv.setImageBitmap(alertbitmap);

sb_red.setOnSeekBarChangeListener(this);
sb_green.setOnSeekBarChangeListener(this);
sb_blue.setOnSeekBarChangeListener(this);

}
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO 自动生成的方法存根

}
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO 自动生成的方法存根

}
// 停止滑动进度条，才设置颜色变化，节省内存
public void onStopTrackingTouch(SeekBar seekBar) {
float red=1;
float green=1;
float blue=1;
switch (seekBar.getId()) {
case R.id.sb_red:
red = seekBar.getProgress()/128.0f;
break;
case R.id.sb_green:
green = seekBar.getProgress()/128.0f;
break;
case R.id.sb_blue:
blue = seekBar.getProgress()/128.0f;
break;

default:
break;
}
ColorMatrix cm = new ColorMatrix();
cm.set(new float[] {    red, 0, 0, 0, 0,
0, green, 0, 0, 0,
0, 0, blue, 0, 0,
0, 0, 0, 1, 0 });

paint.setColorFilter(new ColorMatrixColorFilter(cm));
canvas.drawBitmap(srcbitmap, new Matrix(), paint);
iv.setImageBitmap(alertbitmap);
}

}