前言：
到了第六週，也只剩下三週，要好好努力了． 感覺這個禮拜的內容有點多，看來得仔細把筆記做一下，也希望都能熟悉各個元件的用法．
筆記:
- Graphic 有兩種畫的方式:
- Draw on canvas: 比較複雜，需要變動的繪圖．
- Draw on view: 比較簡單，不需要變動的部分．
- Draw on View:
- 可以有兩種方式來達成，將所有需要的外觀用xml來敘述，或是寫在程式碼裡面的MainActivity的OnCreate也是可以．
- xml 可以是引用其他的xml，比如說顏色敘述可以是另外一個xml
// In main.xml
android:background="@drawable/sq2"
// In drawable/sq2.xml
< ?xml version="1.0" encoding="utf-8"?>
< shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
< solid android:color="#FFFFFF00" />
< stroke
android:width="25dp"
android:color="#FFFF0000" />
< /shape>
- Draw on Canvas:
- 透過View 來達成: (比較少更新)
- 透過Canvas 提供的View 來使用
- 透過 OnDraw 來更新畫面
- 透過SurfaceView 來達成： (需要常更新)
- 具有比較好的效能來更新UI
- 不是屬於UI Drawing Thread來更新畫面．
- 更新方式: (透過Surface callback)
- surfaceCreated()
- surfaceChanged()
- sufaceDestroyed()
- 使用流程:
- SufaceHolder.lockCanvas() 先把UI resource 鎖定
- 透過類似CCanvas.drawBitmap 來更新畫面
- SufaceHolder.unlockCanvasAndPost() 來歸還UI resource
- View Animation:
- TransitionDrawable:
- 用於兩個Drawable資源的切換，不過僅支援fade in/out的過場特效
- Animation:
- 可以做許多不同的Animation，比如說Alpha 變換（也就是fade in/out) 或是 rotate ， translate與 scale(大小)．
- ValueAnimator:
- 可以透過onAnimationUpdate callback 來調整每個animation 要改變的數值
- ViewPropertyAnimator:
- 每個view本身都有一個 .animate() 的ViewPropertyAnimator可以取用
- 可以透過 Runnable去串接下一個Runnable來達成連續Animation的效果
// TransitionDrawable
Drawable[] layers = new Drawable[2]; //Two drawable in list
layers[0] = new ColorDrawable(Color.TRANSPARENT);
layers[1] = new BitmapDrawable(bitmap);
TransitionDrawable drawable = new TransitionDrawable(layers);
image.setImageDrawable(drawable);
drawable.startTransition(300);
// Animation java code
// Create animation
mAnim = AnimationUtils.loadAnimation(this, R.anim.view_animation);
// Set Animation in ImageView when get focus
mImageView.startAnimation(mAnim);
// Animation xml
< alpha //fade in/out
android:duration="3000"
android:fromAlpha="0.0"
android:interpolator="@android:anim/linear_interpolator"
android:toAlpha="1.0" />
< rotate //rotate
android:duration="4000"
android:fromDegrees="0"
android:interpolator="@android:anim/accelerate_interpolator"
android:pivotX="50%"
android:pivotY="50%"
android:startOffset="3000"
android:toDegrees="720" />
// View PropertyAnimation
fadeIn.run(); // Run first runnable
Runnable fadeIn = new Runnable() {
public void run() {
mImageView.animate().setDuration(3000)
.setInterpolator(new LinearInterpolator()).alpha(1.0f)
.withEndAction(rotate);
//Call next runnable rotate.
}
};
- Multiple Touch Event:
- OnTouch event handle MotionEvent:
- Pointer ID: 代表著每一個觸碰的點．當有multiple touch發生的時候，Pointer ID 就有複數個．
- MotionEvent.ACTION_MOVE.ACTION_POINTER_UP: 也是可能有多個pointer ID依序傳入．
- MotionEvent.ACTION_MOVE: 是一次傳入一個群組的 id，你需要一個個去拿來處理．
- OnTouch event handle by GestureDetector:
- GestureDetector可以幫你判別是何種手勢，並且依據支援的手勢來呼叫
- 如果需要增加新的手勢，需要使用GestureBuilder並且把檔案複製到App
- 檔案從 /mnt/sdcard/gestures
- 到 /res/raw 目錄夾
- 客製化手勢使用流程:
- 先使用 GesutureLibraries 把客製化的手勢讀進來
- 輸入新的手勢之後，會得到一個預測的手勢陣列．取出分數最高的來處理
/*
* Multiple touch handle by MotionEvent
*/
// Init frame layout object
FrameLayout mFrame = (FrameLayout) findViewById(R.id.frame);
// Create and set on touch listener
mFrame.setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getActionMasked()) {
// Show new MarkerView
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_POINTER_DOWN: {
int pointerIndex = event.getActionIndex();
int pointerID = event.getPointerId(pointerIndex);
// Each pointerID represent one finger movement. ex: 2 fingers will call twice in this function.
... // Do something about handle in each finger point down.
break;
}
// Handle move as group.
case MotionEvent.ACTION_MOVE: {
for (int idx = 0; idx < event.getPointerCount(); idx++) {
int ID = event.getPointerId(idx);
MarkerView marker = mActiveMarkers.get(ID);
if (null != marker) {
// Do something with marker
}
}
}
break;
}
/*
* Multiple touch handle by Gestture Detector and Custom Gestures
*/
// Load custom gestures
GestureLibrary mLibrary = GestureLibraries.fromRawResource(this, R.raw.gestures);
if (!mLibrary.load()) {
finish();
}
public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) {
// Get gesture predictions
ArrayList predictions = mLibrary.recognize(gesture);
// Get highest-ranked prediction
if (predictions.size() > 0) {
Prediction prediction = predictions.get(0);
// Ignore weak predictions
if (prediction.score > 2.0) { //limited prediction score must higher 2.0
if (prediction.name.equals("CUSTOM_GESTURE_ONE")) {
// Do something.
}
}
</pre>
- Multiple Media Player
- 啟動MediaPlayer流程:
- setDataSource()
- prepare()
- start()
- 啟動MediaRecorder流程 (以錄音為例):
- setAudioSource(MediaRecorder.AudioSource.MIC)
- setOutputFormat(MediaRecorder.OutputFormat.XXX)
- setOutputFile()
- setAudioEncoder(MediaRecorder.AudioEncoder.XXX)
- prepare()
- start()
// Start recording with MediaRecorder
private void startRecording() {
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setOutputFile(mFileName);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
try {
mRecorder.prepare();
} catch (IOException e) {
Log.e(TAG, "Couldn't prepare and start MediaRecorder");
}
mRecorder.start();
}
// Playback audio using MediaPlayer
private void startPlaying() {
mPlayer = new MediaPlayer();
try {
mPlayer.setDataSource(mFileName);
mPlayer.prepare();
mPlayer.start();
} catch (IOException e) {
Log.e(TAG, "Couldn't prepare and start MediaPlayer");
}
}
**參考資源:**
- Android中圖片璇轉與縮放
- [http://fecbob.pixnet.net/blog/post/36421426-android%E4%B8%AD%E5%AF%A6%E7%8F%BE%E5%9C%96%E7%89%87%E5%8F%8A%E5%8B%95%E7%95%AB%E7%9A%84%E7%B8%AE%E6%94%BE%E5%92%8C%E6%97%8B%E8%BD%89(%E8%BD%89)](http://fecbob.pixnet.net/blog/post/36421426-android%E4%B8%AD%E5%AF%A6%E7%8F%BE%E5%9C%96%E7%89%87%E5%8F%8A%E5%8B%95%E7%95%AB%E7%9A%84%E7%B8%AE%E6%94%BE%E5%92%8C%E6%97%8B%E8%BD%89(%E8%BD%89))
- About TransitionDrawable
- [http://jason1peng.blogspot.tw/2013/01/android-ui-1-cross-fading.html](http://jason1peng.blogspot.tw/2013/01/android-ui-1-cross-fading.html)
- TransitionDrawable fade in/out
- [http://givemepass.blogspot.tw/2012/03/xml.html](http://givemepass.blogspot.tw/2012/03/xml.html)
