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I. RectF and Rect 1. Does it contain a point boolean contains(float x, float y) An example can be written based on this: Draw a rectangle to determine if your finger is in range. public class BasisView extends View { private int mX, mY; private RectF rectF; private Paint mPaint; public BasisView(Context context) { ...

2. What is the use of generics? 3. How to define and use generics? 1. What is generics? The popular understanding of generics is that many types allow us to program without specifying specific types by using the concept of parameterized types 2. What is the use of generics? Generics is a security mechanism introduced by JDK 1.5 and a techn ...

@Override public void requestChildFocus(View child, View focused) { if (!mIsLayoutDirty) { scrollToChild(focused); } else { mChildToScrollTo = focused; } super.requestChildFocus(child, focused); } Because the requestLayout() method was called before addViewInner: @Override public void requestLayout() { mIsLayou ...

INITIALIZING initial state CREATED created status ACTIVITY_CREATED   fully created but not started STARTED creates and starts, visible and inoperable RESUMED creation is started and operable [picture uploading... (image-1940e7-1557923091355-0)] This article only explains the CREATED, STARTED and RESUMED states. Since the mState ...

android:layout_width="match_parent" android:layout_height="match_parent"/> ...... </LinearLayout> `````` // MainActivity.java @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ...

1.1. Higher order function when function is used as function parameter Here we introduce sumBy{} higher-order functions in strings. Take a look at the source code first //  Source code of sumBy function public inline fun CharSequence.sumBy(selector: (Char) -> Int): Int {     var sum: Int = 0     for (element in this) {         ...

registerServerSocketFromEnv registers the server socket for cross process communication. Binder communication is not used here.preload() to perform the preload operationgcAndFinalize(), take the initiative to conduct a garbage collection before forkSystemServerforkSystemServer(), create SystemServer processrunSelectLoop(), waiting for the socke ...

The following GIF diagram shows the layout jump without a picture placeholder: See the full example in DartPad If you have cached a picture placeholder in your app, you can use FadeInImage Widgets to display placeholders.If you want to use a widget instead of a picture as a placeholder, you can use Image.frameBuilder&nbs ...

Does try catch affect program performance? First, try catch is used to minimize the scope as much as possible. When no exception is thrown within the try catch scope, the performance impact is small, but when an exception is thrown, the performance impact is multiplied.Specifically, I have conducted a simple test for the following three cases ...

mExecutorService.submit(new Runnable() { @Override public void run() { AVUtils.audioPlay(input_video_file_path); } }); break; } } @Override public void onFinish() { runOnUiThread(new Runnable() { @Override public vo ...