Android开发在画板上画些东西,甩一甩手机实现画板上的东西变成泼墨效果...
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发布时间：2022-05-10 09:59
共1个回答
热心网友
时间：2022-04-20 00:08
直接看代码，注释都写清楚了
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public class MainActivity extends Activity {
private ImageView iv;
private Bitmap baseBitmap;
private Canvas canvas;
private Paint paint;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.iv = (ImageView) this.findViewById(R.id.iv);
// 创建一张空白图片
baseBitmap = Bitmap.createBitmap(480, 640, Bitmap.Config.ARGB_8888);
// 创建一张画布
canvas = new Canvas(baseBitmap);
// 画布背景为灰色
canvas.drawColor(Color.GRAY);
// 创建画笔
paint = new Paint();
// 画笔颜色为红色
paint.setColor(Color.RED);
// 宽度5个像素
paint.setStrokeWidth(5);
// 先将灰色背景画上
canvas.drawBitmap(baseBitmap, new Matrix(), paint);
iv.setImageBitmap(baseBitmap);
iv.setOnTouchListener(new OnTouchListener() {
int startX;
int startY;
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// 获取手按下时的坐标
startX = (int) event.getX();
startY = (int) event.getY();
break;
case MotionEvent.ACTION_MOVE:
// 获取手移动后的坐标
int stopX = (int) event.getX();
int stopY = (int) event.getY();
// 在开始和结束坐标间画一条线
canvas.drawLine(startX, startY, stopX, stopY, paint);
// 实时更新开始坐标
startX = (int) event.getX();
startY = (int) event.getY();
iv.setImageBitmap(baseBitmap);
break;
}
return true;
}
});
}
public void save(View view) {
try {
File file = new File(Environment.getExternalStorageDirectory(),
System.currentTimeMillis() + ".jpg");
OutputStream stream = new FileOutputStream(file);
baseBitmap.compress(CompressFormat.JPEG, 100, stream);
stream.close();
// 模拟一个广播，通知系统sdcard被挂载
Intent intent = new Intent();
intent.setAction(Intent.ACTION_MEDIA_MOUNTED);
intent.setData(Uri.fromFile(Environment
.getExternalStorageDirectory()));
sendBroadcast(intent);
Toast.makeText(this, "保存图片成功", 0).show();
} catch (Exception e) {
Toast.makeText(this, "保存图片失败", 0).show();
e.printStackTrace();
}
}
}
简单的布局文件
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<relativelayout 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" tools:context=".MainActivity">
<button android:id="@+id/button1" android:onclick="save" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignparentbottom="true" android:text="保存图片">
<imageview android:layout_above="@id/but
http://www.2cto.com/kf/201401/273814.html追问我表达错了，重点不是画板，重点是甩一甩然后画的东西有泼墨的效果那里
追答没整明白
