Eigene View in separatem Thread zeichnen

1<!-- main.xml -->
2<?xml version="1.0" encoding="utf-8"?>
3<FrameLayout
4 xmlns:android="http://schemas.android.com/apk/res/android"
5 android:orientation="vertical"
6 android:id="@+id/framelayout0"
7 android:background="#0000ff"
8 android:layout_width="fill_parent"
9 android:layout_height="fill_parent">
10</FrameLayout>
11
12public class UFOActivity extends Activity {
13 private UFOView ufoView;
14
15 @Override
16 public void onCreate(Bundle savedInstanceState) {
17 super.onCreate(savedInstanceState);
18 setContentView(R.layout.main);
19
20 // UI vervollständigen
21 ufoView = new UFOView(this);
22
23 FrameLayout fl = (FrameLayout) findViewById(R.id.framelayout0);
24 fl.addView(ufoView);
25 }
26}
27
28public class UFOView extends View {
29 private float xpos = -1;
30 private float ypos = -1;
31 private Bitmap ufoBitmap;
32 private int touchX;
33 private int touchY;
34 Canvas cvm;
35 boolean async=true;
36 boolean invalid=false;
37
38 public UFOView(Context c) {
39 super(c);
40 // lade Hintergrund
41 //this.setBackgroundResource(R.drawable.hintergrund);
42 // lade Bitmap für UFO
43 Resources resources = getResources();
44 ufoBitmap = BitmapFactory.decodeResource(resources, R.drawable.ufo); //zum Test png-Bild nehmen
45 setFocusable(true);
46 if (async) new MyAsyncTask().execute(cvm);
47 }
48
49 @Override
50 protected void onDraw(Canvas canvas) {
51 super.onDraw(canvas);
52 if (async) { //**** Variante mit Zeichnen in separatem Thread (MyAsyncTask)
53/* ************ dieser Teil funktionierte leider nicht
54 if (invalid) { //Aufruf onDraw indirekt von 'onPostExecute'
55 canvas=cvm; //die dort erstellte Canvas
56 invalid=false;
57 return;
58 }
59*/
60 cvm=canvas;
61 //bewirkt Aufruf Methode 'doInBackground', Abarbeitung in separatem Thread
62 new MyAsyncTask().execute(cvm);
63 } else { //**** Variante ohne Zeichnen in separatem Thread
64 // Startposition getWidth() funktioniert nicht in onCreate() oder
65 // onStart()
66 if (xpos == -1 && ypos == -1) {
67 xpos = getWidth() / 2;
68 ypos = getHeight() / 2;
69 }
70
71 // UFO-Bitmap einzeichnen
72 Paint iconPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
73
74 if (ufoBitmap != null) {
75 canvas.drawBitmap(ufoBitmap, xpos - ufoBitmap.getWidth() / 2, ypos
76 - ufoBitmap.getHeight() / 2, iconPaint);
77 }
78 }
79 }
80
81 @Override
82 public boolean onKeyDown(int keyCode, KeyEvent event) {
83 if (keyCode == KeyEvent.KEYCODE_DPAD_UP) {
84 ypos -= 5;
85 }
86 if (keyCode == KeyEvent.KEYCODE_DPAD_RIGHT) {
87 xpos += 5;
88 }
89 if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN) {
90 ypos += 5;
91 }
92 if (keyCode == KeyEvent.KEYCODE_DPAD_LEFT) {
93 xpos -= 5;
94 }
95 if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
96 xpos = getWidth() / 2;
97 ypos = getHeight() / 2;
98 }
99 if (async)
100 new MyAsyncTask().execute(cvm);
101 else
102 invalidate();
103 return super.onKeyDown(keyCode, event);
104 }
105
106 @Override
107 public boolean onTouchEvent(MotionEvent event) {
108 int aktion = event.getAction();
109
110 if(aktion == MotionEvent.ACTION_DOWN) {
111 touchX = (int) event.getX();
112 touchY = (int) event.getY();
113 }
114 if(aktion == MotionEvent.ACTION_UP) {
115 int tx = (int) event.getX();
116 int ty = (int) event.getY();
117 if( (touchX - tx) > 20) {
118 xpos -= 25;
119 } else if ((touchX - tx) <= -20){
120 xpos += 25;
121 }
122 if( (touchY - ty) > 20) {
123 ypos -= 25;
124 } else if( (touchY - ty) <= -20) {
125 ypos += 25;
126 }
127 }
128 if (async)
129 new MyAsyncTask().execute(cvm);
130 else
131 invalidate();
132 return true; // super.onTouchEvent(event);
133 }
134
135/*
136 * To use AsyncTask you must subclass it. AsyncTask uses generics and varargs.
137 * The parameters are the following:
138 * AsyncTask <TypeOfVarArgParams , ProgressValue , ResultValue> .
139 * TypeOfVarArgParams is passed into the doInBackground() method as input,
140 * ProgressValue is used for progress information and
141 * ResultValue must be returned from doInBackground() method and is passed to onPostExecute() as parameter.
142 */
143 private class MyAsyncTask extends AsyncTask<Canvas,Void,Canvas> {
144 protected Canvas doInBackground(Canvas... c) {
145 Canvas cv;
146 if (c[0] != null)
147 cv=c[0];
148 else
149 cv = new Canvas();
150 if (xpos == -1 && ypos == -1) {
151 xpos = getWidth() / 2;
152 ypos = getHeight() / 2;
153 }
154 // UFO-Bitmap einzeichnen
155 Paint iconPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
156
157 if (ufoBitmap != null) {
158 cv.drawBitmap(ufoBitmap, xpos - ufoBitmap.getWidth() / 2, ypos
159 - ufoBitmap.getHeight() / 2, iconPaint);
160 }
161 return cv;
162 }
163 protected void onPostExecute(Canvas cv) {
164 cvm = cv;
165 invalid=true;
166 invalidate();
167 }
168 }
169}