android 拖拽图片&拖动浮动按钮到处跑

来自老外：

拖拽图片效果

方法一：

布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Button android:id="@+id/btn" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="拖动看看~~" />
</LinearLayout>

　　

方法二：

 

import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.Button;

public class DraftTest extends Activity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		final Button btn = (Button) findViewById(R.id.btn);

		btn.setOnTouchListener(new OnTouchListener() {
			int[] temp = new int[] { 0, 0 };

			public boolean onTouch(View v, MotionEvent event) {

				int eventaction = event.getAction();

				int x = (int) event.getRawX();
				int y = (int) event.getRawY();

				switch (eventaction) {

				case MotionEvent.ACTION_DOWN: // touch down so check if the
					temp[0] = (int) event.getX();
					temp[1] = y - v.getTop();
					break;

				case MotionEvent.ACTION_MOVE: // touch drag with the ball
					v.layout(x - temp[0], y - temp[1], x + v.getWidth()
							- temp[0], y - temp[1] + v.getHeight());

//					v.postInvalidate();
					break;

				case MotionEvent.ACTION_UP:
					break;
				}

				return false;
			}

		});

	}
}

　　

另一种：

 

import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.Button;

public class DraftTest extends Activity {
	/** Called when the activity is first created. */

	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		DisplayMetrics dm = getResources().getDisplayMetrics();
		final int screenWidth = dm.widthPixels;
		final int screenHeight = dm.heightPixels - 50;

		final Button b = (Button) findViewById(R.id.btn);

		b.setOnTouchListener(new OnTouchListener() {

			int lastX, lastY;

			public boolean onTouch(View v, MotionEvent event) {
				// TODO Auto-generated method stub
				switch (event.getAction()) {
				case MotionEvent.ACTION_DOWN:
					lastX = (int) event.getRawX();
					lastY = (int) event.getRawY();
					break;
				case MotionEvent.ACTION_MOVE:
					int dx = (int) event.getRawX() - lastX;
					int dy = (int) event.getRawY() - lastY;

					int left = v.getLeft() + dx;
					int top = v.getTop() + dy;
					int right = v.getRight() + dx;
					int bottom = v.getBottom() + dy;

					if (left < 0) {
						left = 0;
						right = left + v.getWidth();
					}

					if (right > screenWidth) {
						right = screenWidth;
						left = right - v.getWidth();
					}

					if (top < 0) {
						top = 0;
						bottom = top + v.getHeight();
					}

					if (bottom > screenHeight) {
						bottom = screenHeight;
						top = bottom - v.getHeight();
					}

					v.layout(left, top, right, bottom);

					lastX = (int) event.getRawX();
					lastY = (int) event.getRawY();

					break;
				case MotionEvent.ACTION_UP:
					break;
				}
				return false;
			}
		});
	}
}

　　

再一个，浮动按钮的实现。 
主要功能： 
点击按钮可以进行拖动； 
当点击按钮时按钮会出现于所有按钮的最上方；