一个小程序：Instrumentation的使用

本来是想练习Matrix的，没想到写了一个自定义View，监听它的ASWD键后，不知道该如何按下ASWD（手机上一般都没实体按键了）。于是：

一个自定义View：

public class MyView extends View {

    private final Bitmap bitmap;
    private int width;
    private int height;
    private Matrix matrix = new Matrix();
    private boolean isScale = false;
    //设置倾斜度
    private float sx = 0.0f;
    //缩放比例
    private float scale = 1.0f;

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        //获得位图
        bitmap = ((BitmapDrawable) context.getResources().getDrawable(R.drawable.a)).getBitmap();
        //获得位图宽
        width = bitmap.getWidth();
        height = bitmap.getHeight();
        //当前视图获得焦点
        this.setFocusable(true);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //重置Matrix
        matrix.reset();
        if (!isScale) {
            //旋转Matrix
            matrix.setSkew(sx, 0);
        } else {
            matrix.setScale(scale, scale);
        }
        //根据原始位图和Matrix创建新图片
        Bitmap bitmap1 = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
        //绘制新位图
        canvas.drawBitmap(bitmap1, matrix, null);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode) {
            //向左倾斜
            case KeyEvent.KEYCODE_A:
                isScale = false;
                sx += 0.1;
                postInvalidate();
                break;
            //向右倾斜
            case KeyEvent.KEYCODE_D:
                isScale = false;
                sx -= 0.1;
                postInvalidate();
                break;
            //放大
            case KeyEvent.KEYCODE_W:
                isScale = true;
                if (scale < 2.0)
                    scale += 0.1;
                postInvalidate();
                break;
            //缩小
            case KeyEvent.KEYCODE_S:
                isScale = true;
                if (scale > 0.5)
                    scale -= 0.1;
                postInvalidate();
                break;
        }
        return super.onKeyDown(keyCode, event);
    }
}

然后是Activity里的实现（把按钮的点击事件传递给WASD）：

public class MatrixActivity extends Activity {

    private Button left;
    private Button right;
    private Button top;
    private Button bottom;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_matrix);
        left = (Button) findViewById(R.id.left);
        right = (Button) findViewById(R.id.right);
        top = (Button) findViewById(R.id.top);
        bottom = (Button) findViewById(R.id.bottom);

        left.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                sendKeyEvent(29);

            }
        });
        right.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                sendKeyEvent(32);
            }
        });
        top.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                sendKeyEvent(51);
            }
        });

        bottom.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                sendKeyEvent(47);
            }
        });
    }
    public static void sendKeyEvent(final int KeyCode) {
        new Thread() {     //不可在主线程中调用
            public void run() {
                try {
                    Instrumentation inst = new Instrumentation();
                    inst.sendKeyDownUpSync(KeyCode);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

        }.start();
    }
}