Intent in = new Intent();
in.setAction(Intent.ACTION_MEDIA_MOUNTED);
in.setData(Uri.fromFile(Environment.getRootDirectory()));
this.sendBroadcast(in);
// 从图库中选择一张图片
Intent intent = new Intent();
intent.setAction("android.intent.action.PICK");
intent.setType("image/*");
intent.addCategory(Intent.CATEGORY_DEFAULT);
this.startActivityForResult(intent, 0);
所以我们需要发送一个装载sd卡挂载操作的广播
package cn.zengfansheng.paint;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
import android.widget.Toast;
public class MainActivity extends Activity {
private ImageView iv;
private Canvas canvas;
private Paint paint;
private Bitmap mutableBitmap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) this.findViewById(R.id.iv);
// TODO 给图片注册一个手指的触摸事件, 触摸屏幕的时候 根据手指的变化 画线
iv.setOnTouchListener(new OnTouchListener() {
private int startX;// 开始x坐标
private int startY;// 开始y坐标
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:// 手指第一次触摸到屏幕
System.out.println("摸到了。。。");
startX = (int) event.getX();
startY = (int) event.getY();
break;
case MotionEvent.ACTION_UP:// 手指离开屏幕一瞬间
System.out.println("松手了。。。");
break;
case MotionEvent.ACTION_MOVE:// 手指在屏幕上移动
System.out.println("移动了。。。");
int newX = (int) event.getX();
int newY = (int) event.getY();
System.out.println("画线:("+startX+","+startY+")~~("+newX+","+newY+")");
canvas.drawLine(startX, startY, newX, newY, paint);
// 重新更新开始坐标
startX = (int) event.getX();
startY = (int) event.getY();
iv.setImageBitmap(mutableBitmap);
break;
}
return true;// FIXME true，消费掉该事件，false，反之。
}
});
}
/**
* TODO 一、从图库中选择一张图片
* @param view
*/
public void pick(View view){
// 模拟一个操作，重新装载sd卡的动作
Intent in = new Intent();
in.setAction(Intent.ACTION_MEDIA_MOUNTED);
in.setData(Uri.fromFile(Environment.getRootDirectory()));
this.sendBroadcast(in);
// 从图库中选择一张图片
Intent intent = new Intent();
intent.setAction("android.intent.action.PICK");
intent.setType("image/*");
intent.addCategory(Intent.CATEGORY_DEFAULT);
this.startActivityForResult(intent, 0);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (data != null) {
try {
// TODO 获取要查看的图片的路径 Uri(Immutable URI reference)
Uri uri = data.getData();
// 得到从图库中选择的图片做背景，但只是一个只读的Bitmap，不可编辑
InputStream is = this.getContentResolver().openInputStream(uri);
Bitmap bitmap = BitmapFactory.decodeStream(is);
// 创建一个可以编辑的Bitmap
mutableBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());
// TODO 1、创建一个画布，以一个指定的bitmap为背景// 2、在画布上画背景
canvas = new Canvas(mutableBitmap);// The bitmap must be mutable
// TODO 3、创建一支画笔，并设置相应的参数
paint = new Paint();
paint.setColor(Color.RED);
paint.setStrokeWidth(8);
// FIXME 为啥是原来的bitmap4、参考着 原图 bitmap 把内容画在 alterbitmap
canvas.drawBitmap(bitmap, new Matrix(), paint);
// 5、
iv.setImageBitmap(mutableBitmap);
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* TODO 二、保存涂鸦修改后的图片到sdcard
* @param view
*/
public void save(View view){
try {
File file = new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis()+".jpg");
FileOutputStream fos = new FileOutputStream(file);
mutableBitmap.compress(CompressFormat.JPEG, 100, fos);
Toast.makeText(getApplicationContext(), "保存成功", 1).show();
fos.close();
// 模拟一个重新插入sd卡的操作
Intent intent = new Intent();
intent.setAction(Intent.ACTION_MEDIA_MOUNTED);
intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory()));
sendBroadcast(intent);
} catch (IOException e) {
Toast.makeText(this, "保存失败", 1).show();
e.printStackTrace();
}
}
}