Android 在EditText上覆盖onDraw

我正在编写EditText的一个子类，允许用户用手指在上面画画。为此，我创建了一个名为drawing的布尔值，如果为真，则将EditText置于绘图模式，而键盘则不会打开，如果为假，则允许用户打开键盘，并在绘图模式下保持绘图

绘图代码基于名为FingerPaint的Google Android示例。在打算将其实现到EditText之前，代码是在view的子类上实现的，并且工作得很好，但问题是将EditText与布局中的该视图相结合会降低性能

有很多代码可以做到这一点，因为它可以用来实现两个不同的掩码过滤器，向代码中添加一些在这个类中本地未使用的行

我的问题是，当我重写onDraw（）时，绘图为false，文本不会显示给其他用户，但会显示键盘和书写线（|）

这是我的代码：

import android.content.Context;
import android.graphics.*;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.EditText;

public class DrawEditText extends EditText {

    private Bitmap  mBitmap;
    private Canvas  mCanvas;
    private Path    mPath;
    private Paint   mBitmapPaint;
    private Paint   mPaint;
    private MaskFilter  mEmboss;
    private MaskFilter  mBlur;

    private Boolean drawing;

    public DrawEditText(Context c) {
        super(c);


        //This initializes all the objects
        mPath = new Path();
        mBitmapPaint = new Paint(Paint.DITHER_FLAG);

        mPaint = new Paint();
        mPaint.setColor(Color.BLACK);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(5);
        mPaint.setAntiAlias(true);

        mEmboss = new EmbossMaskFilter(new float[] { 1, 1, 1 },
                0.4f, 6, 3.5f);

        mBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL);

        drawing = true;
    }
    public DrawEditText(Context c, AttributeSet attrs) {
        super(c, attrs);

        //This initializes all the objects
        mPath = new Path();
        mBitmapPaint = new Paint(Paint.DITHER_FLAG);

        mPaint = new Paint();
        mPaint.setColor(Color.BLACK);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(5);
        mPaint.setAntiAlias(true);

        mEmboss = new EmbossMaskFilter(new float[] { 1, 1, 1 },
                0.4f, 6, 3.5f);

        mBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL);

        drawing = true;
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
        mCanvas = new Canvas(mBitmap);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
        canvas.drawPath(mPath, mPaint);
    }

    private float mX, mY;
    private static final float TOUCH_TOLERANCE = 4;

    private void touch_start(float x, float y) {
        mPath.reset();
        mPath.moveTo(x, y);
        mX = x;
        mY = y;
    }
    private void touch_move(float x, float y) {
        float dx = Math.abs(x - mX);
        float dy = Math.abs(y - mY);
        if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
            mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);
            mX = x;
            mY = y;
        }
    }
    private void touch_up() {
        mPath.lineTo(mX, mY);
        // commit the path to our offscreen
        mCanvas.drawPath(mPath, mPaint);
        // kill this so we don't double draw
        mPath.reset();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float x = event.getX();
        float y = event.getY();

        //This conditional makes that if not it's drawing no points are saved and no points are drawed
        if (drawing){
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    touch_start(x, y);
                    invalidate();
                    break;
                case MotionEvent.ACTION_MOVE:
                    touch_move(x, y);
                    invalidate();
                    break;
                case MotionEvent.ACTION_UP:
                    touch_up();
                    invalidate();
                    break;
            }
            return true;
        } else {
            return super.onTouchEvent(event);
        }
    }

    public void changePaint(int stroke, int color){
        mPaint.setColor(color);
        mPaint.setStrokeWidth(stroke);
    }
    public void clear(){
        mCanvas.drawColor(0x00AAAAAA);
        mCanvas.drawColor( 0, PorterDuff.Mode.CLEAR );
    }
    public void changeBrush(int id){
        //String[] ids={"emboss", "blur", "another"};
        switch (id) {
        case 0:
            mPaint.setMaskFilter(mEmboss);
            break;
        case 1:
            mPaint.setMaskFilter(mBlur);                
            break;
        case 2:
            mPaint.setMaskFilter(null);         
            break;
        default:
            mPaint.setMaskFilter(null);
            break;
        }
    }
    public void eraser(){
        mPaint.setMaskFilter(null); 
        mPaint.setColor(0x00AAAAAA);
    }

    public void setDrawing(Boolean drawing){
        this.drawing = drawing;
    }

    public Boolean isDrawing(){
        return drawing;
    }
}

---

只需给EditText一个机会来绘制自己的内容：

@Override
protected void onDraw(Canvas canvas) {
    if(drawing) {
      canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
      canvas.drawPath(mPath, mPaint);
    } else {
      super.onDraw(canvas);
    }
}

---

它解决了我的问题，但我想要的是始终显示这两个东西，文本和绘图，所以我删除了条件，然后它按照我想要的方式工作。