java - Android 中可拖动圆圈内的文本

Question

我正在尝试创建一个 Android 应用程序，用户可以将任何圆圈拖动到另一个圆圈上，并且文本框应显示这两个圆圈的总和。每次程序启动时，它都应该显示具有随机位置和 1 -9 范围内的随机数字的圆圈。

不幸的是，我距离这个目标还差得很远，我已经创建了一个圆圈，但是当我尝试拖动它时，应用程序崩溃了。还请帮助我完成该应用程序的其余功能。谢谢。

最终输出应如下所示:

MainActivity.java

package com.dragandadd;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        FrameLayout main = (FrameLayout) findViewById(R.id.activity_main);
        main.addView(new Ball(this,50,50,25));

        main.addView(new Ball(this,50,50,25));

        main.setOnTouchListener(new View.OnTouchListener() {
            public boolean onTouch(View v, MotionEvent e) {
                float x = e.getX();
            float y = e.getY();
                FrameLayout flView = (FrameLayout) v;
            flView.addView(new Ball(getParent(), x,y,25));
            return true;
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

Ball.java

package com.dragandadd;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;

public class Ball extends View {
    final float x;
    final float y;
    final int r;
    final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

    public Ball(Context context, float x, float y, int r) {
        super(context);
        mPaint.setColor(0xFFFF0000);
        this.x = x;
        this.y = y;
        this.r = r;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawCircle(x, y, r, mPaint);
    }
}

activity_main

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#FF66FF33" />

Answer 1

使用此方法拖动图像

How to implement Drag and Drop in android 2.2?

还有这个

http://blahti.wordpress.com/2011/01/17/moving-views-part-2/