package com.example.test;

import android.app.Activity;
import android.content.Context;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MainActivity extends Activity {
	private static GridView mGridView;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		mGridView = new GridView(getApplicationContext());
		MAdapter adapter = new MAdapter(mGridView.getContext(), new String[]{
			"你好1","你好2","你好3","你好4","你好5","你好6","你好7","你好8","你好9","你好10",
			"你好11","你好12","你好13","你好14","你好15","你好16","你好17","你好18","你好19","你好20",
			"你好21","你好22","你好23","你好24","你好25","你好26","你好27","你好28","你好29","你好30"
		});
		LinearLayout headLayout = new LinearLayout(getApplicationContext());
		LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
				LinearLayout.LayoutParams.FILL_PARENT, 300);
		headLayout.setLayoutParams(params);
		headLayout.setBackgroundColor(Color.RED);
		mGridView.setAdapter(adapter);
		mGridView.setNumColumns(2);
		setContentView(mGridView);
	}
	
	static class MAdapter extends BaseAdapter{

		private String[] items;
		private Context context;
		public MAdapter(Context context, String[] items) {
			this.items = items;
			this.context = context;
		}
		
		@Override
		public int getCount() {
			return items.length;
		}

		@Override
		public Object getItem(int position) {
			return position;
		}

		@Override
		public long getItemId(int position) {
			return position;
		}
		
		@Override
		public int getItemViewType(int position) {
			return super.getItemViewType(position);
		}
		
		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			
			TextView textView = null;
			if (position %4 == 0) {
				textView = new MyText(context);
				AbsListView.LayoutParams params = new AbsListView.LayoutParams(
						AbsListView.LayoutParams.FILL_PARENT, 100);
				textView.setLayoutParams(params);
				textView.setTextColor(Color.BLACK);
				textView.setTextSize(20);
				textView.setText(items[position]);
				textView.setBackgroundColor(0x88FF0000);
				textView.setGravity(Gravity.LEFT | Gravity.CENTER_VERTICAL);
			} else {
				textView = new TextView(context);
				AbsListView.LayoutParams params = new AbsListView.LayoutParams(
						AbsListView.LayoutParams.FILL_PARENT, 200);
				textView.setLayoutParams(params);
				textView.setTextColor(Color.BLACK);
				textView.setTextSize(20);
				textView.setText(items[position]);
				textView.setVisibility(View.VISIBLE);
				if (position %4 == 1) {		// GridView的行高由该行最后一个元素的高度决定
					AbsListView.LayoutParams params2 = new AbsListView.LayoutParams(
							AbsListView.LayoutParams.FILL_PARENT, 100);
					textView.setLayoutParams(params2);
					textView.setVisibility(View.INVISIBLE);
				}
				textView.setGravity(Gravity.CENTER);
			}
			return textView;
		}
		
		class MyText extends TextView {
			public MyText(Context context) {
				super(context);
			}
			@Override
			protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
				super.onMeasure(widthMeasureSpec, heightMeasureSpec);
				int targetWidth = mGridView.getMeasuredWidth()
	                    - mGridView.getPaddingLeft()
	                    - mGridView.getPaddingRight();
	            widthMeasureSpec = MeasureSpec.makeMeasureSpec(targetWidth,
	                    MeasureSpec.getMode(widthMeasureSpec));
	            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
			}
		}
	}
}