Question

我的申请表有问题。这是为了在屏幕上拖动球。我的问题是（我认为）我的布局设计（我不知道如何做到这一点）。我在MainActivity中的布局如下：

        //Creates 3 layouts
    LinearLayout view = (LinearLayout)LayoutInflater.from(this).inflate(R.layout.main, null);
    view.setClickable(true);
    RelativeLayout layout = new RelativeLayout(this);
    final DrawView custom = new DrawView(this);
    //Creates the background and sets the background.
    RelativeLayout background = new RelativeLayout(this);
    Resources res = getResources();
    Drawable drawable = res.getDrawable(R.drawable.achtergrond);
    background.setBackground(drawable);
    layout.addView(background, new LinearLayout.LayoutParams(widthOfBackground, LayoutParams.WRAP_CONTENT));
    //Rules of the background, forced to the right
    RelativeLayout.LayoutParams params1 = (RelativeLayout.LayoutParams)background.getLayoutParams();
    params1.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
    background.setLayoutParams(params1);
    //Adding of the layouts to the main layout.
    layout.addView(custom); 
    layout.addView(view);
    //Shows the view to the user
    setContentView(layout);

我做了3个布局： - 一个主要的xml布局（视图） - 一个RelativeLayout，其中放入其他布局。 - 例如：在其中制作球的drawView。

我的问题是当我在主布局中创建一个按钮时。按钮确实显示，但我无法使用它。如果我在MainActivity中创建了一个onClick方法，它就不会做任何事情。此外，如果我尝试在MainActivity中创建一个Toast消息，它就不会显示出来。

我非常感谢您对我的布局的任何帮助或提示！

drawView（自定义）的代码是：

package HVA.getConnected.toptopo;

import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Point;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.view.MotionEvent;
import android.view.View;

public class DrawView extends View {
protected static final int REFRESH = 0;
public ColorBall[] colorballs = new ColorBall[1]; // array that holds the balls
private int balID = 0; // variable to know what ball is being dragged

public DrawView(Context context) {
    super(context);
    setFocusable(true); //necessary for getting the touch events
    // setting the start point for the balls

    Point point1 = new Point(200,200);
    Point point1a = new Point(755,502);

    // declare each ball with the ColorBall class
    colorballs[0] = new ColorBall(context,R.drawable.vlag_frankrijk, point1, R.drawable.vlag_frankrijk_vink, point1a);

}

// the method that draws the balls
@Override 
protected void onDraw(Canvas canvas) {
        //draw the balls on the canvas
    for (ColorBall ball : colorballs) {
        canvas.drawBitmap(ball.getBitmap(), ball.getX(), ball.getY(), null);
      }

}

// events when touching the screen
public boolean onTouchEvent(MotionEvent event) {
    int eventaction = event.getAction(); 

    int X = (int)event.getX(); 
    int Y = (int)event.getY(); 

    switch (eventaction ) { 

    case MotionEvent.ACTION_DOWN: // touch down so check if the finger is on a ball
        balID = 0;
        System.out.println("debug 1");
        for (ColorBall ball : colorballs) {
            // check if inside the bounds of the ball (circle)
            // get the center for the ball
            int centerX = ball.getX() + 25;
            int centerY = ball.getY() + 25;

            // calculate the radius from the touch to the center of the ball
            double radCircle  = Math.sqrt( (double) (((centerX-X)*(centerX-X)) + (centerY-Y)*(centerY-Y)));

            // if the radius is smaller then 23 (radius of a ball is 22), then it must be on the ball
            if (radCircle > 0 && radCircle < 23){
                balID = ball.getID();
                break;
            }

            // check all the bounds of the ball (square)
            if (X > ball.getX() && X < ball.getX()+50 && Y > ball.getY() && Y < ball.getY()+50){
                balID = ball.getID();
                break;
            }
          }
        System.out.println("debug 2");
         break; 


    case MotionEvent.ACTION_MOVE:   // touch drag with the ball
        // move the balls the same as the finger
        if (balID > 0) {
            colorballs[balID-1].setX(X-25);
            colorballs[balID-1].setY(Y-25);
        }

        break; 

    case MotionEvent.ACTION_UP: 
        // touch drop - just do things here after dropping
        if (balID > 0){
            ColorBall a = colorballs[balID-1];
            if(a.getX() > a.getDestX()-100 && a.getX() < a.getDestX()+100 &&
                    a.getY() > a.getDestY()-100 && a.getY() < a.getDestY()){
                System.out.println("___Drag X & Y is good");
                colorballs[balID-1].setCanMove(false);
            }
        }
        break; 
    } 
    // redraw the canvas
    invalidate(); 
    return true; 

}
}

我已经研究了一下，Toast消息在MainActivity类中有效，但按钮没有。该程序现在不能再运行了。我补充说：

        b1 = (Button) findViewById(R.id.btn1);
    b1.setOnClickListener(this);

我得到的错误是我需要使用OnClickListener强制转换onclicklistener。但是，当我这样做时，它不能再运行了。它与错误ClassCastException崩溃，我不知道如何解决这个问题。

onClick方法：

    @Override
public void onClick(View v) {
    // Perform action on click
    switch(v.getId()) {
    case R.id.btn1:
        System.out.println(".....");
        Toast.makeText(this, "hoi?", Toast.LENGTH_LONG).show();
        break;
    }

}}

Toast是：

Toast.makeText(this, "text", Toast.LENGTH_LONG).show();

Answer 1

像这样使用

        Button btn = (Button) findViewById(R.id.btn1);
                 btn.setOnClickListener(new OnClickListener() {
                         public void onClick(View v) {
                showToastMessage(R.id.btn1);

                         }
                      });}


                //showToastMessage(int id) method definition here

              public void showToastMessage(int id)
             {    
                  switch(id) {
               case id:
              System.out.println(".....");
           Toast.makeText(this, "hoi?", Toast.LENGTH_LONG).show();
               break;
                 }

                 }

Answer 2

布局设置使用onclickListeners破坏了应用程序，我现在在我的XML文件中有了View类，它解决了我所有的问题。

由于布局设计，布局按钮和toast无法正常工作 - 更新

2 个答案: