Question

感谢您的回复，我想我没有解释清楚，我想要的是在同一个画布上绘制和绘画。在下面的代码中，我试图拖动“mBitmap”，但我不能:(

class Panel extends SurfaceView implements SurfaceHolder.Callback {

private Bitmap mBitmap;
private ViewThread mThread;
private Path path = new Path();

private final int paintColor = Color.BLACK;
private Paint drawPaint;

private int mX;
private int mY;

public Panel(Context context) {
    super(context);
    mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);

    getHolder().addCallback(this);
    mThread = new ViewThread(this);
    setupPaint();
}

public void doDraw(Canvas canvas) {
    canvas.drawColor(Color.GREEN);
    Paint paint = new Paint();
    int ancho = canvas.getWidth();
    int largo = canvas.getHeight();
    paint.setARGB(255, 255, 0, 0);
    paint.setStrokeWidth(6);
    canvas.drawLine(0, (largo/2), ancho, (largo/2), paint);
    canvas.drawBitmap(mBitmap, mX, mY, null);
    canvas.drawPath(path, drawPaint);
}
private void setupPaint() {
    drawPaint = new Paint();
    drawPaint.setColor(paintColor);
    drawPaint.setAntiAlias(true);
    drawPaint.setStrokeWidth(5);
    drawPaint.setStyle(Paint.Style.STROKE);
    drawPaint.setStrokeJoin(Paint.Join.ROUND);
    drawPaint.setStrokeCap(Paint.Cap.ROUND);
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
    if (!mThread.isAlive()) {
        mThread = new ViewThread(this);
        mThread.setRunning(true);
        mThread.start();
    }
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    if (mThread.isAlive()) {
        mThread.setRunning(false);
    }
}

public boolean onTouchEvent(MotionEvent event) {
    float pointX = event.getX();
    float pointY = event.getY();
    switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            path.moveTo(pointX, pointY);
            break;
        case MotionEvent.ACTION_MOVE:
            path.lineTo(pointX, pointY);
            break;
        default:
            return false;
    }

    postInvalidate();
    return true;
}

抱歉，但我不太了解。如果有人能指导我，我非常感激！

Answer 1

以下是一些可以帮助您入门的代码：

<强> DragDropLinearLayout.java

package com.example.views;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;

public class DragDropLinearLayout extends LinearLayout {
    private static final String TAG = DragDropLinearLayout.class.getSimpleName();

    private boolean dragging = false;
    private View draggedView = null;

    private float touchX, touchY;

    public DragDropLinearLayout(Context context) {
        super(context);
    }

    public DragDropLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public void addView(View v, int index, ViewGroup.LayoutParams params) {
        super.addView(v, index, params);

        v.setOnLongClickListener(new OnLongClickListener() {

            @Override
            public boolean onLongClick(View v) {
                dragging = true;
                draggedView = v;

                Log.d(TAG, "Dragging started!");
                return true;
            }
        });
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(canvas);

        if (dragging) {
            canvas.save();
            canvas.translate(touchX - draggedView.getWidth(), touchY - draggedView.getHeight());
            canvas.scale(1.5f, 1.5f);
            canvas.clipRect(0, 0, draggedView.getWidth(), draggedView.getHeight());
            draggedView.draw(canvas);
            canvas.restore();
        }
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_UP:
                break;
            case MotionEvent.ACTION_DOWN:
                touchX = event.getX();
                touchY = event.getY();
                break;
            case MotionEvent.ACTION_MOVE:
                break;
        }

        return dragging || super.onInterceptTouchEvent(event);
    }

    public void onDragComplete() {
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_UP:
                dragging = false;
                onDragComplete();

                invalidate();
                Log.d(TAG, "Dragging stopped!");

                break;
            case MotionEvent.ACTION_DOWN:
                touchX = event.getX();
                touchY = event.getY();

                break;
            case MotionEvent.ACTION_MOVE:
                touchX = event.getX();
                touchY = event.getY();

                if (dragging) {
                    getParent().requestDisallowInterceptTouchEvent(true);
                    invalidate();
                }

                break;
        }

        return dragging || super.onTouchEvent(event);
    }
}

<强> activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<com.example.views.DragDropLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/rootView"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher"/>
</com.example.views.DragDropLinearLayout>

这是做什么

此示例使用名为LinearLayout的自定义DragDropLinearLayout实现。它允许您拖放添加到LinearLayout的单个ImageView。

如何运作

所有繁重的工作都由DragDropLinearLayout完成。 DragDropLinearLayout的作用是首先将OnLongClickListener添加到添加到其中的所有子项。侦听器将当前被长时间单击的任何视图标记为当前正在拖动的视图。

它还具有触摸侦听器，以便它可以确定用户当前拖动视图的位置。它最终绘制了用户手指所在位置拖动视图的克隆。

Android中的Paint and Drag＆amp; Drop

1 个答案: