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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.example.android.apis.view;
     18 
     19 import com.example.android.apis.R;
     20 
     21 import android.app.ListActivity;
     22 import android.content.Context;
     23 import android.graphics.PixelFormat;
     24 import android.os.Bundle;
     25 import android.os.Handler;
     26 import android.view.View;
     27 import android.view.LayoutInflater;
     28 import android.view.WindowManager;
     29 import android.view.WindowManager.LayoutParams;
     30 import android.widget.AbsListView;
     31 import android.widget.ArrayAdapter;
     32 import android.widget.ListView;
     33 import android.widget.TextView;
     34 
     35 
     36 /**
     37  * Another variation of the list of cheeses. In this case, we use
     38  * {@link AbsListView#setOnScrollListener(AbsListView.OnScrollListener)
     39  * AbsListView#setOnItemScrollListener(AbsListView.OnItemScrollListener)} to display the
     40  * first letter of the visible range of cheeses.
     41  */
     42 public class List9 extends ListActivity implements ListView.OnScrollListener {
     43 
     44     private final class RemoveWindow implements Runnable {
     45         public void run() {
     46             removeWindow();
     47         }
     48     }
     49 
     50     private RemoveWindow mRemoveWindow = new RemoveWindow();
     51     Handler mHandler = new Handler();
     52     private WindowManager mWindowManager;
     53     private TextView mDialogText;
     54     private boolean mShowing;
     55     private boolean mReady;
     56     private char mPrevLetter = Character.MIN_VALUE;
     57 
     58     @Override
     59     public void onCreate(Bundle savedInstanceState) {
     60         super.onCreate(savedInstanceState);
     61 
     62         mWindowManager = (WindowManager)getSystemService(Context.WINDOW_SERVICE);
     63 
     64         // Use an existing ListAdapter that will map an array
     65         // of strings to TextViews
     66         setListAdapter(new ArrayAdapter<String>(this,
     67                 android.R.layout.simple_list_item_1, mStrings));
     68 
     69         getListView().setOnScrollListener(this);
     70 
     71         LayoutInflater inflate = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
     72 
     73         mDialogText = (TextView) inflate.inflate(R.layout.list_position, null);
     74         mDialogText.setVisibility(View.INVISIBLE);
     75 
     76         mHandler.post(new Runnable() {
     77 
     78             public void run() {
     79                 mReady = true;
     80                 WindowManager.LayoutParams lp = new WindowManager.LayoutParams(
     81                         LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT,
     82                         WindowManager.LayoutParams.TYPE_APPLICATION,
     83                         WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
     84                                 | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
     85                         PixelFormat.TRANSLUCENT);
     86                 mWindowManager.addView(mDialogText, lp);
     87             }});
     88     }
     89 
     90     @Override
     91     protected void onResume() {
     92         super.onResume();
     93         mReady = true;
     94     }
     95 
     96 
     97     @Override
     98     protected void onPause() {
     99         super.onPause();
    100         removeWindow();
    101         mReady = false;
    102     }
    103 
    104     @Override
    105     protected void onDestroy() {
    106         super.onDestroy();
    107         mWindowManager.removeView(mDialogText);
    108         mReady = false;
    109     }
    110 
    111 
    112 
    113 
    114     public void onScroll(AbsListView view, int firstVisibleItem,
    115             int visibleItemCount, int totalItemCount) {
    116         if (mReady) {
    117             char firstLetter = mStrings[firstVisibleItem].charAt(0);
    118 
    119             if (!mShowing && firstLetter != mPrevLetter) {
    120 
    121                 mShowing = true;
    122                 mDialogText.setVisibility(View.VISIBLE);
    123             }
    124             mDialogText.setText(((Character)firstLetter).toString());
    125             mHandler.removeCallbacks(mRemoveWindow);
    126             mHandler.postDelayed(mRemoveWindow, 3000);
    127             mPrevLetter = firstLetter;
    128         }
    129     }
    130 
    131 
    132     public void onScrollStateChanged(AbsListView view, int scrollState) {
    133     }
    134 
    135 
    136     private void removeWindow() {
    137         if (mShowing) {
    138             mShowing = false;
    139             mDialogText.setVisibility(View.INVISIBLE);
    140         }
    141     }
    142 
    143     private String[] mStrings = Cheeses.sCheeseStrings;
    144 }
    145