android viewgroup

First of all, I've been searching the internet for a long time and I haven't found a way to explain it, so I tried to write it myself.1. I have customized a viewgroup that inherits Relativelayout.The Java code is as follows:/*** Simple Custom three Avatar *@authorm.z*/ Public classMygroupheaderimgextendsRelativelayout { Publicmygroupheaderimg (Context context, AttributeSet attrs) {Super(context, attrs); This. Mcontext =context; MView= Inflate (contex

In Android, the layout is directly or indirectly inherited from the viewgroup class. The direct subclasses of viewgroup currently include:Absolutelayout, adapterview Among them, drawerlayout, pagertitlestrip, scyclingpanelayout, and viewpager are supported by Android API level 4 (version 1.6) and later

When inheriting the ViewGroup class, you must override two methods: onMeasure and onLayout. 1. Call the setMeasuredDimension method in onMeasure. Void android. view. View. setMeasuredDimension (int measuredWidth, int measuredHeight) In onMeasure (int, int), you must call setMeasuredDimension (int width, int height) to store the width and height of the measurement. If you do not do so, an exception Illega

During development, there are sometimes some requirements. Simply using the layout and controls provided by the system does not meet our development needs. Therefore, you can customize the layout (viewgroup) by yourself) and controls (view. Here, I will use a simple example to explain the basic process of custom viewgroup, hoping to help those who do not know the process. First, we want to implement the fol

In development, there are some requirements that can sometimes be met. The layout and control system not only provides the use to meet our development, so this time on the line, usually your own custom layout (ViewGroup) and control (View) that. I am here, we will use a simple example, when they explain their definition viewgroup basic flow, I hope to help friends do not understand the process.First, we wan

One view: the rendering process of viewgroupViewgroup painting involves two steps: 1. Measure 2. LayoutCall the callback function in these two steps: 1. onmeasure () 2. onlayout ()1. onmeasure () in this function, viewgroup will accept the size of the childview request, and store it in childview through the measure (newwidthmeasurespec, heightmeasurespec) function of childview, so that getmeasuredwidth () of childview ()The value of andgetmeasuredheig

There are three important ways to inherit ViewGroup , so let's take a look at the following:1.onlayout methodprotectedvoidOnLayout (BooleanChangedintLeftintTopintRightintBottom) {}When we inherit ViewGroup , we will provide this method in addition to the constructor, and we can see that the method is defined in the source code of ViewGroup , that is, the parent c

Question: How does the system know if the user is sliding a (the page in the black box) or B (the FGM in the red box)Answer:-dispatchtouchevent, Onintercepttouchevent, ontoucheventProblem Resolution:This can be said to be an Android event handling problem, first introduce the great God said these three events "Each view subclass in the Android system has the following three methods that are closely related

1, ViewGroup can add the control, you can also use 　　Once a few parts of the space are found to inherit ViewGroup, then rewrite the Onmeasure method, measure all the children inside, and then rewrite the layout method to lay out the location of the children's view.2 understand the principle of groupview, and according to the source code simulation when leaving the screen when the screen back to the homepage

Main.xmlMainactivityPackage Com.example.simplelayout;import Android.app.activity;import Android.os.bundle;public class MainActivity Extends Activity { @Override public void OnCreate (Bundle savedinstancestate) { super.oncreate ( Savedinstancestate); Setcontentview (R.layout.main); }}MylinlayoutPackage Com.example.simplelayout;import Android.content.context;import Android.util.attributeset;import Android.view.view;import android.view.viewgroup;/** */** onmeasure (): Measure

The View class is the parent class of ViewGroup. ViewGroup has all the features of View. ViewGroup is mainly used to act as the View container and manage the View as its own child, of course, the child can also be of the ViewGroup type. The View class is generally used for drawing operations. It overrides its onDraw me