使用拖放listview拖动文本？
目前我正在开发需要使用拖放列表视图的应用程序。但是当我拖放列表项时，我无法拖放文本。均值列表能够拖放但文本保持在同一位置。那么如何用列表项拖动文本？
Main.java类
package com.example.dragdroplistview;
import android.app.ListActivity;
import android.content.Context;
import android.graphics.Color;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
public class Main extends ListActivity {
private ListView mExampleList;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mExampleList = getListView();
System.out.println("position values = "+mExampleList);
mExampleList.setOnCreateContextMenuListener(this);
((DDListView) mExampleList).setDropListener(mDropListener);
mExampleList.setAdapter(new ExampleArrayAdapter(getApplicationContext(),
R.layout.rowexample,new String[]{"Row one", "Row two", "Row tree"}));
}
//ArrayAdapter
private class ExampleArrayAdapter extends ArrayAdapter<String>{
private Context mContext;
private int mLayoutId;
private String[] mListContent;
public ExampleArrayAdapter(Context context, int textViewResourceId,
String[] objects) {
super(context, textViewResourceId, objects);
mContext = context;
mLayoutId = textViewResourceId;
mListContent = objects;
}
public View getView(int position, View rowView, ViewGroup parent) {
if (rowView != null) {
return rowView;
}
LayoutInflater inflater= LayoutInflater.from(mContext);
View v = inflater.inflate(mLayoutId, null);
v.setBackgroundColor(Color.RED);
TextView rowTitle = (TextView)v.findViewById(R.id.text1);
rowTitle.setText(mListContent[position]);
return v;
}
}
//Drop Listener
private DDListView.DropListener mDropListener =
new DDListView.DropListener() {
public void drop(int from, int to) {
}
};
}
DDListView.java类
package com.example.dragdroplistview;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.ListView;
public class DDListView extends ListView {
private int mDragPos; // which item is being dragged
private int mFirstDragPos; // where was the dragged item originally
private int mDragPoint; // at what offset inside the item did the user grab it
private int mCoordOffset; // the difference between screen coordinates and coordinates in this view
private WindowManager mWindowManager;
private WindowManager.LayoutParams mWindowParams;
private Rect mTempRect = new Rect();
//dragging elements
private Bitmap mDragBitmap;
private ImageView mDragView;
private int mHeight;
private int mUpperBound;
private int mLowerBound;
private int mTouchSlop;
private int mItemHeightHalf;
private int mItemHeightNormal;
private int mItemHeightExpanded;
private DragListener mDragListener;
private DropListener mDropListener;
public DDListView(Context context, AttributeSet attrs) {
super(context, attrs);
Resources res = getResources();
mItemHeightNormal = res.getDimensionPixelSize(R.dimen.normal_height);
mItemHeightHalf = mItemHeightNormal / 2;
mItemHeightExpanded = res.getDimensionPixelSize(R.dimen.expanded_height);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (mDragListener != null || mDropListener != null) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
int x = (int) ev.getX();
int y = (int) ev.getY();
int itemnum = pointToPosition(x, y);
if (itemnum == AdapterView.INVALID_POSITION) {
break;
}
ViewGroup item = (ViewGroup) getChildAt(itemnum - getFirstVisiblePosition());
mDragPoint = y - item.getTop();
mCoordOffset = ((int)ev.getRawY()) - y;
item.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(item.getDrawingCache());
startDragging(bitmap, y);
mDragPos = itemnum;
mFirstDragPos = mDragPos;
mHeight = getHeight();
int touchSlop = mTouchSlop;
mUpperBound = Math.min(y - touchSlop, mHeight / 3);
mLowerBound = Math.max(y + touchSlop, mHeight * 2 /3);
return false;
}
}
return super.onInterceptTouchEvent(ev);
}
private int myPointToPosition(int x, int y) {
if (y < 0) {
int pos = myPointToPosition(x, y + mItemHeightNormal);
if (pos > 0) {
return pos - 1;
}
}
Rect frame = mTempRect;
final int count = getChildCount();
for (int i = count - 1; i >= 0; i--) {
final View child = getChildAt(i);
child.getHitRect(frame);
if (frame.contains(x, y)) {
return getFirstVisiblePosition() + i;
}
}
return INVALID_POSITION;
}
private int getItemForPosition(int y) {
int adjustedy = y - mDragPoint - mItemHeightHalf;
int pos = myPointToPosition(0, adjustedy);
if (pos >= 0) {
if (pos <= mFirstDragPos) {
pos += 1;
}
} else if (adjustedy < 0) {
pos = 0;
}
return pos;
}
private void adjustScrollBounds(int y) {
if (y >= mHeight / 3) {
mUpperBound = mHeight / 3;
}
if (y <= mHeight * 2 / 3) {
mLowerBound = mHeight * 2 / 3;
}
}
private void unExpandViews(boolean deletion) {
for (int i = 0;; i++) {
View v = getChildAt(i);
if (v == null) {
if (deletion) {
int position = getFirstVisiblePosition();
int y = getChildAt(0).getTop();
setAdapter(getAdapter());
setSelectionFromTop(position, y);
}
layoutChildren();
v = getChildAt(i);
if (v == null) {
break;
}
}
ViewGroup.LayoutParams params = v.getLayoutParams();
params.height = mItemHeightNormal;
v.setLayoutParams(params);
v.setVisibility(View.VISIBLE);
}
}
private void doExpansion() {
int childnum = mDragPos - getFirstVisiblePosition();
if (mDragPos > mFirstDragPos) {
childnum++;
}
View first = getChildAt(mFirstDragPos - getFirstVisiblePosition());
for (int i = 0;; i++) {
View vv = getChildAt(i);
if (vv == null) {
break;
}
int height = mItemHeightNormal;
int visibility = View.VISIBLE;
if (vv.equals(first)) {
if (mDragPos == mFirstDragPos) {
visibility = View.INVISIBLE;
} else {
height = 1;
}
} else if (i == childnum) {
if (mDragPos < getCount() - 1) {
height = mItemHeightExpanded;
}
}
ViewGroup.LayoutParams params = vv.getLayoutParams();
params.height = height;
vv.setLayoutParams(params);
vv.setVisibility(visibility);
}
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if ((mDragListener != null || mDropListener != null) && mDragView != null) {
int action = ev.getAction();
switch (action) {
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
Rect r = mTempRect;
mDragView.getDrawingRect(r);
stopDragging();
if (mDropListener != null && mDragPos >= 0 && mDragPos < getCount()) {
mDropListener.drop(mFirstDragPos, mDragPos);
}
unExpandViews(false);
break;
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_MOVE:
int x = (int) ev.getX();
int y = (int) ev.getY();
dragView(x, y);
int itemnum = getItemForPosition(y);
if (itemnum >= 0) {
if (action == MotionEvent.ACTION_DOWN || itemnum != mDragPos) {
if (mDragListener != null) {
mDragListener.drag(mDragPos, itemnum);
}
mDragPos = itemnum;
doExpansion();
}
int speed = 0;
adjustScrollBounds(y);
if (y > mLowerBound) {
// scroll the list up a bit
speed = y > (mHeight + mLowerBound) / 2 ? 16 : 4;
} else if (y < mUpperBound) {
// scroll the list down a bit
speed = y < mUpperBound / 2 ? -16 : -4;
}
if (speed != 0) {
int ref = pointToPosition(0, mHeight / 2);
if (ref == AdapterView.INVALID_POSITION) {
//we hit a divider or an invisible view, check somewhere else
ref = pointToPosition(0, mHeight / 2 + getDividerHeight() + 64);
}
View v = getChildAt(ref - getFirstVisiblePosition());
if (v!= null) {
int pos = v.getTop();
setSelectionFromTop(ref, pos - speed);
}
}
}
break;
}
return true;
}
return super.onTouchEvent(ev);
}
private void startDragging(Bitmap bm, int y) {
stopDragging();
mWindowParams = new WindowManager.LayoutParams();
mWindowParams.gravity = Gravity.TOP;
mWindowParams.x = 0;
mWindowParams.y = y - mDragPoint + mCoordOffset;
mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
| WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
| WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
| WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS;
mWindowParams.format = PixelFormat.TRANSLUCENT;
mWindowParams.windowAnimations = 0;
Context context = getContext();
ImageView v = new ImageView(context);
int backGroundColor = context.getResources().getColor(R.color.appwidget_text);
v.setBackgroundColor(backGroundColor);
v.setImageBitmap(bm);
mDragBitmap = bm;
mWindowManager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
mWindowManager.addView(v, mWindowParams);
mDragView = v;
}
private void dragView(int x, int y) {
mWindowParams.y = y - mDragPoint + mCoordOffset;
mWindowManager.updateViewLayout(mDragView, mWindowParams);
}
private void stopDragging() {
if (mDragView != null) {
WindowManager wm = (WindowManager)getContext().getSystemService(Context.WINDOW_SERVICE);
wm.removeView(mDragView);
mDragView.setImageDrawable(null);
mDragView = null;
}
if (mDragBitmap != null) {
mDragBitmap.recycle();
mDragBitmap = null;
}
}
public void setDragListener(DragListener l) {
mDragListener = l;
}
public void setDropListener(DropListener l) {
mDropListener = l;
}
public interface DragListener {
void drag(int from, int to);
}
public interface DropListener {
void drop(int from, int to);
}
public interface RemoveListener {
void remove(int which);
}
}
main.xml中
<?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"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/main_title"/>
<!-- Custom list view goes here :) -->
<com.example.dragdroplistview.DDListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:drawSelectorOnTop="false"
android:fastScrollEnabled="true" android:clickable="false" android:drawingCacheQuality="high">
</com.example.dragdroplistview.DDListView>
</LinearLayout>
rowexample.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView
android:id="@+id/text1"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:gravity="center_vertical"
android:paddingLeft="6dip"
android:minHeight="?android:attr/listPreferredItemHeight"
android:text="TEXTO" android:layout_width="wrap_content"/>
</LinearLayout>
listview的图片，其中我无法拖动文本 - 第一行，第二行，行树。
1 个答案:
答案 0 :(得分：0)
将主XML从LinearLayout更改为RelativeLayout
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:id="@+id/txttitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/main_title"
android:layout_alignPatentTop="true"
/>
<!-- Custom list view goes here :) -->
<com.example.dragdroplistview.DDListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:drawSelectorOnTop="false"
android:fastScrollEnabled="true" android:clickable="false" android:drawingCacheQuality="high"
android:layout_below="@+id/txttitle"
>
</com.example.dragdroplistview.DDListView>
</RelativeLayout>
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