我在标签主机中添加了2个片段。在第二个片段中我可以做一些绘图。当我在这两个片段之间切换时，我的第二个片段中的绘图被删除了。我不知道为什么？
这是第二个片段。
public class DrawingFragment extends BaseFragment implements android.view.View.OnClickListener {
private Context context = null;
private Bitmap backGroundBitmap = null;
private DrawingViewHolder viewHolder = null;
/**
*
*/
@Override
public void onAttach(Activity arg0) {
super.onAttach(arg0);
this.context=arg0;
}
public DrawingFragment() {
}
public DrawingFragment(Bitmap bitmap) {
this.backGroundBitmap = bitmap;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.drawing_dialog, container,false);
viewHolder = new DrawingViewHolder();
viewHolder.initUiContents(view);
return view;
}
/**
*
* @author Qandil
*
*/
private class DrawingViewHolder{
private Button btnDoneDrawing = null;
private Button btnEraserDrawing = null;
private Button btnPencilDrawing = null;
private Button btnDeleteDrawing = null;
private LinearLayout llDrawingMain = null;
private DrawView drawingView = null;
private void initUiContents(View view){
btnDoneDrawing = (Button) view.findViewById(R.id.btn_drawing_done);
btnEraserDrawing = (Button) view.findViewById(R.id.btn_drawing_eraser);
btnPencilDrawing = (Button) view.findViewById(R.id.btn_drawing_pencil);
btnDeleteDrawing = (Button) view.findViewById(R.id.btn_drawing_delete);
llDrawingMain = (LinearLayout) view.findViewById(R.id.ll_drawing_dialog_main);
drawingView = (DrawView)view.findViewById(R.id.custom_dv2);
btnDoneDrawing.setOnClickListener(DrawingFragment.this);
btnEraserDrawing.setOnClickListener(DrawingFragment.this);
btnPencilDrawing.setOnClickListener(DrawingFragment.this);
btnDeleteDrawing.setOnClickListener(DrawingFragment.this);
Drawable dr = new BitmapDrawable(backGroundBitmap);
llDrawingMain.setBackgroundDrawable(dr);
}
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_drawing_done:
((CaseActivity) getActivity()).popFragments();
break;
case R.id.btn_drawing_delete:
((CaseActivity) getActivity()).popFragments();
break;
default:
break;
}
}
/* (non-Javadoc)
* @see android.support.v4.app.Fragment#onDestroyView()
*/
@Override
public void onDestroyView() {
super.onDestroyView();
}
/* (non-Javadoc)
* @see android.support.v4.app.Fragment#onDetach()
*/
@Override
public void onDetach() {
super.onDetach();
}
}
drawing_dialog.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/ll_drawing_dialog_main"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout
android:id="@+id/ll_drawing_dialog"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/img_draw_photo_bg"
android:orientation="vertical" >
<RelativeLayout
android:id="@+id/top_bar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/img_top_bar" >
<TextView
android:id="@+id/tv_draw_picture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="@string/tv_draw_picture"
android:textColor="#ffffff"
android:textSize="18sp"
android:textStyle="bold" />
</RelativeLayout>
<LinearLayout
android:id="@+id/ll_header_drawing_dialog"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@drawable/img_top_bar"
android:gravity="center" >
<Button
android:id="@+id/btn_drawing_done"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/img_drawing_done" />
<Button
android:id="@+id/btn_drawing_eraser"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:background="@drawable/img_drawing_eraser" />
<Button
android:id="@+id/btn_drawing_pencil"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:background="@drawable/img_drawing_pencil" />
<Button
android:id="@+id/btn_drawing_delete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:background="@drawable/img_drawing_dlt" />
</LinearLayout>
<RelativeLayout
android:id="@+id/rlt_drawing_component"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<view
android:id="@+id/custom_dv2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
class="com.avhl.view.activity.DrawView"
android:background="#00000000" />
</RelativeLayout>
</LinearLayout>
</LinearLayout>
DrawView.java
public class DrawView extends View{
private Bitmap cache;
private Queue<PointF> points;
private PointF from;
private Context context;
private Paint paint ;
public DrawView(Context context,AttributeSet attr) {
super(context,attr);
this.context=context;
points = new ConcurrentLinkedQueue<PointF>();
paint = new Paint();
paint.setAntiAlias(true);
paint.setStrokeWidth(8);
paint.setColor(Color.GRAY);
paint.setDither(true); // set the dither to true
paint.setStyle(Paint.Style.FILL_AND_STROKE); // set to STOKE
paint.setStrokeJoin(Paint.Join.ROUND); // set the join to round you want
paint.setStrokeCap(Paint.Cap.ROUND); // set the paint cap to round too
setFocusable(true);
setFocusableInTouchMode(true);
}
/***
* on touch event
*/
@Override
public boolean onTouchEvent(MotionEvent evt) {
setPressed(true);
int pointerIndex = ((evt.getAction() & MotionEvent.ACTION_POINTER_ID_MASK)
>> MotionEvent.ACTION_POINTER_ID_SHIFT);
int pointerId = evt.getPointerId(pointerIndex);
if(pointerId==0){
switch (evt.getAction()) {
case MotionEvent.ACTION_DOWN:
from = new PointF(evt.getX(), evt.getY());
break;
case MotionEvent.ACTION_MOVE:
points.add(new PointF(evt.getX(), evt.getY()));
invalidate();
break;
case MotionEvent.ACTION_UP:
break;
default:
from = null;
}
}else{
return false;
}
return true;
}
/**
*
* @param systemCanvas
*/
@Override
public void onDraw(Canvas systemCanvas) {
int w = getWidth();
int h = getHeight();
if (w == 0 || h == 0)
return;
if (cache == null)
cache = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
// Draw on the cache
Canvas canvas = new Canvas(cache);
drawPoints(points, canvas, paint);
// Draw the cache with the system canvas
systemCanvas.drawBitmap(cache, 0, 0, paint);
}
/*
* for drawing line or dot
*/
private void drawPoints(Queue<PointF> points, Canvas canvas, Paint paint) {
if (from == null)
return;
PointF to;
while ((to = points.poll()) != null) {
canvas.drawLine(from.x, from.y, to.x, to.y, paint);
from = to;
}
}
}
在MianActivity中，我只需通过调用更改的选项卡上的ft.replace（）替换我的第一个片段的DrawingFragment选项卡。
答案 0 :(得分：1)
您可以尝试在片段onCreate中调用Fragment.setRetainInstance(true)。这样可以确保重用相同的片段实例，而不是创建新的片段实例。
如果没有一些代码来展示你在做什么，很难更有帮助