0. 原文拜讀
https://blog.csdn.net/lb377463323/article/details/70275971
1. AlbumSetPage界面資料裝載和界面重新整理,為界面渲染作準備
1. 資料裝載
package com.android.gallery3d.app;
public class AlbumSetPage extends ActivityState implements OnClickListener,...{
private AlbumSetDataLoader mAlbumSetDataAdapter;
@Override
public void onResume() {
super.onResume();
...
mAlbumSetDataAdapter.resume();
...
}
}
- 上接mAlbumSetDataAdapter.resume()
package com.android.gallery3d.app;
public class AlbumSetDataLoader {
public void resume() {
mSource.addContentListener(mSourceListener);
mReloadTask = new ReloadTask();
mReloadTask.start();
}
- 上接 ReloadTask()
// TODO: load active range first
private class ReloadTask extends Thread {
@Override
public void run() {
while (mActive) {
...
// 資料加載完成，進入界面重新整理
executeAndWait(new UpdateContent(info));
}
}
}
1.2 界面重新整理的回調事件
- 上接 executeAndWait(new UpdateContent(info));
private class UpdateContent implements Callable<Void> {
private final UpdateInfo mUpdateInfo;
@Override
public Void call() {
...
for (DataListener l : mDataListener) {
l.onSizeChanged(mSize);
}
...
for (DataListener l : mDataListener) {
l.onContentChanged(info.index);
}
}
}
- 檢視下接口定義
package com.android.gallery3d.app;
public static interface DataListener {
public void onContentChanged(int index);
public void onSizeChanged(int size);
}
-
grep指令檢視實作該接口
目前隻有 AlbumSetSlidingWindow 實作
src/com/android/gallery3d/ui/AlbumSetSlidingWindow.java:40:public class AlbumSetSlidingWindow implements AlbumSetDataLoader.DataListener {
- 檢視 AlbumSetSlidingWindow 事件
package com.android.gallery3d.ui;
// 這裡實作了上述的監聽事件
public class AlbumSetSlidingWindow implements AlbumSetDataLoader.DataListener {
public static interface Listener {
public void onSizeChanged(int size);
public void onContentChanged();
}
@Override
public void onContentChanged(int index) {
...
// 這裡回調了自己的 onContentChanged 事件
if (mListener != null && isActiveSlot(index)) {
mListener.onContentChanged();
}
}
@Override
public void onSizeChanged(int size) {
...
// 這裡回調了自己的 onSizeChanged 事件
if (mListener != null) mListener.onSizeChanged(mSize);
...
}
}
-
grep 指令檢視所有注冊該監聽 implements AlbumSetSlidingWindow.Listener
grep -irn “implements AlbumSetSlidingWindow.Listener” ./路徑
發現隻有唯一一處
src/com/android/gallery3d/ui/AlbumSetSlotRenderer.java:234: private class MyCacheListener implements AlbumSetSlidingWindow.Listener
- 檢視 AlbumSetSlotRenderer 接受的回調事件
package com.android.gallery3d.ui;
public class AlbumSetSlotRenderer extends AbstractSlotRenderer {
private class MyCacheListener implements AlbumSetSlidingWindow.Listener {
@Override
public void onSizeChanged(int size) {
mSlotView.setSlotCount(size);
}
@Override
public void onContentChanged() {
// SlotView重新整理界面
mSlotView.invalidate();
}
}
}
- 檢視 SlotView.invalidate() 重新整理界面函數
package com.android.gallery3d.ui;
public class SlotView extends GLView {
// invalidate() 未重寫，故方法在 GLView
}
- 檢視 GLView.invalidate() 重新整理界面函數
// Request re-rendering of the view hierarchy.
// This is used for animation or when the contents changed.
public void invalidate() {
GLRoot root = getGLRoot();
if (root != null) root.requestRender();
}
- 上述 root.requestRender() 就是請求渲染一幀資料，之後走到Renderer的onDrawFrame方法
package com.android.gallery3d.app.dualcam3d.gl;
public class Renderer implements GLSurfaceView.Renderer {
@Override
public void onDrawFrame(GL10 gl) {
if (mImageBitmap == null) {
return;
}
updateImage();
updateMatrix();
GLES20.glClearColor(0, 0, 0, 0);
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
mMesh.render(mShader);
}
2. 渲染
2.1 檢視 AlbumSetPage.GLView 的 render 方法
package com.android.gallery3d.app;
public class AlbumSetPage extends ActivityState implements OnClickListener, ..{
private final GLView mRootPane = new GLView() {
@Override
protected void render(GLCanvas canvas) {
...
super.render(canvas);
canvas.restore();
}
}；
}
2.2 GLView 的 render 方法
package com.android.gallery3d.ui;
public class GLView {
protected void render(GLCanvas canvas) {
...
for (int i = 0, n = getComponentCount(); i < n; ++i) {
renderChild(canvas, getComponent(i));
}
...
}
protected void renderChild(GLCanvas canvas, GLView component) {
...
//這裡component就是 SlotView，用于繪制每個專輯
component.render(canvas);
...
}
}
2.3 SlotView 的 render 方法
package com.android.gallery3d.ui;
public class SlotView extends GLView {
@Override
protected void render(GLCanvas canvas) {
super.render(canvas);
...
// renderItem就是對每一個專輯進行繪制
for (int i = mLayout.mVisibleEnd - 1; i >= mLayout.mVisibleStart; --i) {
int r = renderItem(canvas, i, 0, paperActive);
if ((r & RENDER_MORE_FRAME) != 0) more = true;
if ((r & RENDER_MORE_PASS) != 0) requestedSlot[requestCount++] = i;
}
...
}
private int renderItem(
GLCanvas canvas, int index, int pass, boolean paperActive) {
canvas.save(GLCanvas.SAVE_FLAG_ALPHA | GLCanvas.SAVE_FLAG_MATRIX);
...
//mRenderer就是 AlbumSetSlotRenderer
int result = mRenderer.renderSlot(
canvas, index, pass, rect.right - rect.left, rect.bottom - rect.top);
...
}
2.4 檢視 AlbumSetSlotRenderer.renderSlot
package com.android.gallery3d.ui;
public class AlbumSetSlotRenderer extends AbstractSlotRenderer {
@Override
public int renderSlot(GLCanvas canvas, int index, int pass, int width, int height) {
AlbumSetEntry entry = mDataWindow.get(index);
int renderRequestFlags = 0;
// 增加非空判斷
if(null == entry){
Log.e(TAG, "render content error: entry is null!");
return renderRequestFlags;
}
// 繪制專輯顯示的縮略圖
renderRequestFlags |= renderContent(canvas, entry, width, height);
// 繪制顯示檔案夾名稱、數目、檔案夾icon的Label
renderRequestFlags |= renderLabel(canvas, entry, width, height);
// 繪制長按選擇專輯時的藍色圖層
renderRequestFlags |= renderOverlay(canvas, index, entry, width, height);
// 畫分割線
renderRequestFlags |= renderDivider(canvas, width, height);
return renderRequestFlags;
}
最終所有專輯都通過canvas繪制出來，canvas是通過OpenGL ES的GLES20.glDrawArrays(type, 0, count)來繪制的，具體自行檢視GLES20Canvas類。
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