Android 画画板

来源：互联网发布：linux 定时唤醒编辑：程序博客网时间：2024/05/01 16:16
public class MainActivity extends AppCompatActivity {    private static final String TAG = "jojo";    private ImageView iv;    private Bitmap srcBitmap;    private Bitmap copyBitmap;    private Paint paint;    private Canvas canvas;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        // 用来显示我们画的内容        iv = (ImageView) findViewById(R.id.iv);        //1 获取原图 bg        srcBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bg);        //2 获取原图的副本 相当于是一个空白的白纸        copyBitmap = Bitmap.createBitmap(srcBitmap.getWidth(), srcBitmap.getHeight(), srcBitmap.getConfig());        // 创建画笔        paint = new Paint();        // 创建一个画布        canvas = new Canvas(copyBitmap);        // 开始作画        canvas.drawBitmap(srcBitmap, new Matrix(), paint);//        canvas.drawLine(20, 30, 50, 80, paint);        iv.setImageBitmap(copyBitmap);        //3 给iv设置一个触摸事件        iv.setOnTouchListener(new View.OnTouchListener() {            int startX = 0;            int startY = 0;            @Override            public boolean onTouch(View v, MotionEvent event) {                // 获取当前事件类型                int action = event.getAction();                switch (action) {                    case MotionEvent.ACTION_DOWN: // 按下                        Log.d(TAG, "onTouch: 摸View");                        // 获取开始位置（划线）                        startX = (int) event.getX();                        startY = (int) event.getY();                        break;                    case MotionEvent.ACTION_MOVE: // 移动                        Log.d(TAG, "onTouch: 移动");                        // 获取结束位置                        int stopX = (int) event.getX();                        int stopY = (int) event.getY();                        // 不停的划线                        canvas.drawLine(startX, startY, stopX, stopY, paint);                        // 再次显示到iv上                        iv.setImageBitmap(copyBitmap);                        // 更新一下开始坐标和结束坐标                        startX = stopX;                        startY = stopY;                        break;                    case MotionEvent.ACTION_UP: // 抬起                        Log.d(TAG, "onTouch: 抬起");                        break;                }                // True if the listener has consumed the event, false otherwise                return true;            }        });    }    // 点击按钮 改变画笔的颜色    public void click1(View v) {        paint.setColor(Color.RED);    }    // 点击按钮 对画笔加粗    public void click2(View v) {        paint.setStrokeWidth(15);    }    // 点击按钮 保存图片    public void click3(View v) {        /**         * format 保存图片的格式         * quality 保存图片的质量         * SystemClock.uptimeMillis() 这个是当前手机的开机时间         */        try {            File file = new File(Environment.getExternalStorageDirectory().getPath(), SystemClock.uptimeMillis() + ".png");            FileOutputStream fos = new FileOutputStream(file);            copyBitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);            // 发送一条广播 欺骗系统图库的应用            Intent mediaScanIntent = new Intent(                    Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);            Uri contentUri = Uri.fromFile(file); //out is your output file            mediaScanIntent.setData(contentUri);            sendBroadcast(mediaScanIntent);        } catch (FileNotFoundException e) {            e.printStackTrace();        }    }}
注意添加写外存权限
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