轉(zhuǎn)載請注明出處：http://www.reibang.com/p/0ea58e77ef57
這個問題百度上一搜一大把，基本上都是說找到和SurfaceView的比例相近的camera預(yù)覽尺寸白筹，但是發(fā)現(xiàn)預(yù)覽時候還是差了點意思拨拓，具體看下面這個回調(diào)就知道是為什么了由捎。
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
Log.i(TAG, "surfaceChanged: " + width + " " + height);
}
從上面的回調(diào)打印的數(shù)據(jù)知道surfaceview的寬高比可能與camera設(shè)置的寬高比不一致伦仍，其實取相近的比例解決不了根本問題合冀。
所以错负，對于此類的解決方法我只想說僅僅相近有神馬用。
那么既然知道surfaceChanged的寬高就是SurfaceView的渲染寬高最筒，那么想辦法把surfaceChanged里的寬高比弄成和camera比例一樣不就行了嘛邮偎，所以看SurfaceView的源碼：
protected void updateWindow(boolean force, boolean redrawNeeded) {
...代碼省略
int myWidth = mRequestedWidth;
if (myWidth <= 0) myWidth = getWidth();
int myHeight = mRequestedHeight;
if (myHeight <= 0) myHeight = getHeight();
...代碼省略
if (creating || formatChanged || sizeChanged
|| visibleChanged || realSizeChanged) {
if (DEBUG) Log.i(TAG, System.identityHashCode(this) + " "
+ "surfaceChanged -- format=" + mFormat
+ " w=" + myWidth + " h=" + myHeight);
if (callbacks == null) {
callbacks = getSurfaceCallbacks();
}
for (SurfaceHolder.Callback c : callbacks) {
c.surfaceChanged(mSurfaceHolder, mFormat, myWidth, myHeight);
}
}
...代碼省略
}
可以看到寬高其實就是調(diào)用的View的getHeight和getWidth或者是mRequestedWidth和mRequestedHeight暑竟。
熟悉了View的自定義就知道getHeight和getWidth都是和View的onMeasure息息相關(guān)繁扎，所以想到重寫onMeasure方法油航。
再從源碼看到關(guān)于mRequestedWidth和mRequestedHeight的賦值
@Override
public void setFixedSize(int width, int height) {
if (mRequestedWidth != width || mRequestedHeight != height) {
mRequestedWidth = width;
mRequestedHeight = height;
requestLayout();
}
}
以下是完整類代碼：
public class ResizeAbleSurfaceView extends SurfaceView {
private int mWidth = -1;
private int mHeight = -1;
public ResizeAbleSurfaceView(Context context) {
super(context);
}
public ResizeAbleSurfaceView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ResizeAbleSurfaceView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
if (-1 == mWidth || -1 == mHeight) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
} else {
setMeasuredDimension(mWidth, mHeight);
}
}
public void resize(int width, int height) {
mWidth = width;
mHeight = height;
getHolder().setFixedSize(width, height);
requestLayout();
invalidate();
}
}
實例化的時候記得調(diào)用resize方法就好了。
注意和camera的預(yù)覽尺寸比例一致邢锯，且寬高記得傳正確扬蕊，不然可能不全屏
