Custom view - extensible collapsexpendview

Custom scalable ViewGroup

design sketch

Specific code and detailed explanation ：

The main points for attention

1. stay OnMeasure Call in measureChild Method , This method calls the child View Of Measure Method , obtain MeasuredWidth and MeasureHeight. The parent... Can then be calculated from these measured values View Height .
2. Execute... In the constructor addView The operation will prepare to add view Add to , Include those not initially shown ImageView, Add a background picture when you click the button on the right , Click again to set the background to blank , After setting View Of requestLayout and invalidate To redraw .

public class CollapsExpendView extends ViewGroup{
	private static String TAG="CollapsExpendView";
    //  Image array   
    private static final int[] ARR_IMAGES = {   
        R.drawable.sample_0,   
        R.drawable.sample_1,   
        R.drawable.sample_2,   
    };
    private TextView textview[];
    private ImageButton button[];
    private ImageView imageView[];
    private Context context;
    private Boolean ifexpend=false;
    private int linearLayout_height,linearLayout_width;
    private static final String[] names={
    	" Dog 111111",
    	" Dog 222222",
    	" Dog 333333"
    };
    private LinearLayout linearLayout[];
	public CollapsExpendView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		// TODO Auto-generated constructor stub
		this.context=context;
		addViewFirst();
	}

	public CollapsExpendView(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
		// TODO Auto-generated constructor stub
		this.context=context;
	}

	public CollapsExpendView(Context context) {
		this(context,null);
		this.context=context;
		// TODO Auto-generated constructor stub
	}
	public void addViewFirst(){
		Log.i(TAG,"addViewFirst");
		linearLayout = new LinearLayout[3];
		textview=new TextView[3];
		button= new ImageButton[3];
		imageView=new ImageView[3];
		for(int i=0;i<3;i++){
			linearLayout[i]=new LinearLayout(context);
			imageView[i]=new ImageView(context);
			// Set width and height , At this time, it is only executed in the constructor , Hasn't arrived yet View Of Measure Stage , call get The height and width obtained by the method are 0;
			LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT);
			linearLayout[i].setOrientation(LinearLayout.HORIZONTAL);
			// For horizontal LinearLayout Add three view
			setLinearLayoutView(linearLayout[i],i);
			linearLayout[i].setLayoutParams(params);
			imageView[i].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
			// Holistic viewGroup Add three vertical view, It's a Layout, A dividing line , A picture （ Because it is wrap_Content Do not show at first ）, One is the dividing line 
			this.addView(linearLayout[i]);
			this.addView(imageView[i]);
			this.addView(getDividerView());
		}	
	}
	public View getDividerView(){
		ImageView divider=new ImageView(context);
		LayoutParams params = new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT);
		divider.setLayoutParams(params);
		divider.setBackgroundResource(R.drawable.category_list_divider);
		return divider;
	}
	@Override
	protected void onLayout(boolean arg0, int arg1, int arg2, int arg3, int arg4) {
		// TODO Auto-generated method stub
		int count = getChildCount();     
		int sumHeight=0;
        // According to each sub View Set the size of , Set each child View The location of 
        for(int i = 0 ;i < count;i++) {
        	View child= getChildAt(i);
        	child.layout(0, sumHeight,child.getMeasuredWidth(), sumHeight+child.getMeasuredHeight());
        	sumHeight+=child.getMeasuredHeight();
        }
	}
	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		super.onDraw(canvas);
	}
/*
 *  A parent view may call more than once on its child views measure(int,int) Method .
 *  for example , The parent view can use unspecified dimensions To measure each of its sub views once to figure out how big they really need to be ,
 *  If the sum of the sizes of all these sub views is not limited to too large or too small , Then it will call again with the exact value measure()
 * （ in other words , If the subviews are not satisfied with the area size they get , Then the parent view will interfere and set the second measurement rule ）.
 * @see android.view.View#onMeasure(int, int)
 */
	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		// TODO Auto-generated method stub
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		// Get parent view The widest display limit of 
		int rw = MeasureSpec.getSize(widthMeasureSpec);
		int rh = MeasureSpec.getSize(heightMeasureSpec);
		Log.i(TAG,"rw: "+rw+"rh: "+rh);
		int count=this.getChildCount();
		int sumHeight=0;// Height accumulation 
		View child=null;
		for (int i = 0; i < count; i++) {
			child = this.getChildAt(i);
			Log.i(TAG,"child：width》》  "+child.getWidth()+"LayoutParams》》 "+child.getLayoutParams().width+"getMeasuredWidth》》 "+child.getMeasuredWidth());
			this.measureChild(child, widthMeasureSpec, heightMeasureSpec); 
			// In the first measurement , Will use UNSPECIFIED Measurer View Expectant size, So in customizing viewgroup in ,
			// call Measurechild Then there will be getMeasureHeight and getMeasureWidth Value 
			Log.i(TAG,"child：width》》  "+child.getWidth()+"LayoutParams》》  "+child.getLayoutParams().width+"getMeasuredWidth》》 "+child.getMeasuredWidth());
			sumHeight+=child.getMeasuredHeight();
		}
		setMeasuredDimension(rw, sumHeight);
	}
	public void setLinearLayoutView(LinearLayout layout,int i){
		// Set up textView
		textview[i] =new TextView(context);
		LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,88);
		textview[i].setLayoutParams(params);
		textview[i].setText(names[i]);
		textview[i].setTextSize(32);
		layout.addView(textview[i],params);
		// Set the fill Layout, The weight is 1
		LayoutParams params2= new LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.WRAP_CONTENT, 1);
		layout.addView(new View(context),params2);
		// Set button 
		button[i]=new ImageButton(context);
		LayoutParams params_button = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);
		button[i].setLayoutParams(params_button);
		button[i].setBackgroundResource(R.drawable.btn_alarms_more);	
		button[i].setOnClickListener(getButtonOnclickListener(button[i],i));
		layout.addView(button[i]);	
	}	
	private OnClickListener getButtonOnclickListener(final ImageButton button, final int i) {
		// TODO Auto-generated method stub
		return new OnClickListener() {
			
			@Override
			public void onClick(View arg0) {
				// TODO Auto-generated method stub
				if(ifexpend==false){// It means contraction , Click to expand 
					button.setBackgroundResource(R.drawable.btn_alarms_up);	
					ifexpend=true;
					imageView[i].setBackgroundResource(ARR_IMAGES[i]);
				}
				else{
					button.setBackgroundResource(R.drawable.btn_alarms_more);	
					ifexpend=false;
					imageView[i].setBackground(null);
				}
				CollapsExpendView.this.requestLayout();
				CollapsExpendView.this.invalidate();
					
			}
		};
	}
}