問題描述
Android：擴展 onTouchEvent 以進行拖動的 ImageView (Android: ImageView that extends onTouchEvent for Drag)
I wrote a simple cards game where the user plays his card doing TAP on one of the three imageviews (the cards) I'd like to add the possibility of playing the card by dragging the ImageView on the "table" (the table is another layout or simply another part of the screen).
I tryed to use the techinc indicated at http://blahti.wordpress.com/2011/01/17/moving-views-part-2/ but as it uses AbsoluteLayout, it introduces a lot of limitations on my current layout, more it requires adjustments depending to the device screen resolution where the app runs. I'd like to avoid this continue using -if possibile- the RelativeLayout. Maybe the starting point is extenting the ImageView adding the onTouch support but i couldn't reproduce the wished effect (drag) Any idea or suggestion or sample code? Thanks!
Just to give an idea, this is the draft of layout. The 3 cards below should be moved via drag.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent"
>
<RelativeLayout android:id="@+id/player_cards_layout"
android:layout_width="fill_parent" android:layout_height="150dip"
android:gravity="center_horizontal"
android:background="#55335588"
android:layout_above="@+id/player_cards_layout"
>
<ImageView android:id="@+id/img_pc_card_1"
android:layout_width="100dip" android:layout_height="150dip"
android:src="@drawable/icon"
/>
</RelativeLayout>
<RelativeLayout android:id="@+id/player_cards_layout"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:gravity="center_horizontal"
android:background="#336699"
>
<ImageView android:id="@+id/img_user_card_1"
android:layout_width="100dip" android:layout_height="150dip"
android:src="@drawable/icon"
/>
<ImageView android:id="@+id/img_user_card_2"
android:layout_width="100dip" android:layout_height="150dip"
android:src="@drawable/icon"
android:layout_toRightOf="@+id/img_user_card_1"
/>
<ImageView android:id="@+id/img_user_card_3"
android:layout_width="100dip" android:layout_height="150dip"
android:src="@drawable/icon"
android:layout_toRightOf="@+id/img_user_card_2"
/>
</RelativeLayout>
</RelativeLayout>
參考解法
方法 1:
here is nice example from link. i hope this will help you.
res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:gravity="center" android:id="@+id/LinearLayout01">
<Button android:layout_width="wrap_content"
android:layout_height="wrap_content" android:id="@+id/btn"
android:text="Drag Me"></Button>
</FrameLayout>
src/com/beanie/example/Home.java
package com.beanie.example;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.FrameLayout.LayoutParams;
public class Home extends Activity implements OnTouchListener {
private final static int START_DRAGGING = 0;
private final static int STOP_DRAGGING = 1;
private Button btn;
private FrameLayout layout;
private int status;
private LayoutParams params;
private ImageView image;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
layout = (FrameLayout) findViewById(R.id.LinearLayout01);
// layout.setOnTouchListener(this);
btn = (Button) findViewById(R.id.btn);
btn.setDrawingCacheEnabled(true);
btn.setOnTouchListener(this);
params = new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT);
}
@Override
public boolean onTouch(View view, MotionEvent me) {
if (me.getAction() == MotionEvent.ACTION_DOWN) {
status = START_DRAGGING;
image = new ImageView(this);
image.setImageBitmap(btn.getDrawingCache());
layout.addView(image, params);
}
if (me.getAction() == MotionEvent.ACTION_UP) {
status = STOP_DRAGGING;
Log.i("Drag", "Stopped Dragging");
} else if (me.getAction() == MotionEvent.ACTION_MOVE) {
if (status == START_DRAGGING) {
System.out.println("Dragging");
image.setPadding((int) me.getRawX(), (int) me.getRawY(), 0, 0);
image.invalidate();
}
}
return false;
}
}
(by Lisitso、user609239)