UI复习-布局管理器GridLayout(计算器界面)

package com.brady.est;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.GridLayout;
import android.widget.GridLayout.LayoutParams;

@SuppressLint("HandlerLeak")
public class MainActivity extends ActionBarActivity {

private String[] buttons={
"1","2","3","+",
"4","5","6","-",
"7","8","9","x",
"0",".","/","="};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

GridLayout gridLayout = (GridLayout)findViewById(R.id.root);

for(int i = 0 ;i<gridLayout.getRowCount()-2;i++){

//按键所在的单元格 行
//从第三行开始
GridLayout.Spec rowSpec = GridLayout.spec(i%gridLayout.getRowCount()+2);

for(int j = 0;j<gridLayout.getColumnCount();j++){

Button button = new Button(this);
button.setText(buttons[i*4+j]);
button.setTextSize(40);

//按键所在的单元格 列
GridLayout.Spec colSpec = GridLayout.spec(j%gridLayout.getColumnCount());

//该单元格布局
GridLayout.LayoutParams layoutParams = new GridLayout.LayoutParams(rowSpec, colSpec);
layoutParams.setGravity(Gravity.FILL);
//向网格组件 添加子组件button以及，该button的布局参数对象
gridLayout.addView(button, layoutParams);
}
}
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}

<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:columnCount="4"
android:rowCount="6"
android:id="@+id/root"
tools:context="com.brady.est.MainActivity" >
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="0"
android:layout_columnSpan="4"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_columnSpan="4"
android:text="清除"/>

</GridLayout>