Android简单计算器界面实现

XML文件：

<?xml version="1.0" encoding="utf-8"?>
<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:rowCount="6"
    android:columnCount="4"
    android:id="@+id/root">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_columnSpan="4"
        android:textSize="50sp"
        android:layout_marginLeft="2pt"
        android:layout_marginRight="2pt"
        android:padding="3pt"
        android:layout_gravity="right"
        android:background="#eee"
        android:textColor="#000"
        android:text="0" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_columnSpan="4"
        android:text="清除"/>

</GridLayout>

MainActivity:

package learn.li.com.learnthree;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.widget.Button;
import android.widget.GridLayout;
import android.widget.TextView;

import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends AppCompatActivity {
    GridLayout gridLayout;
    String[] chars = new String[]{
              "7","8","9","÷",
              "4","5","6","x",
              "1","2","3","-",
              ".","0","=","="
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        gridLayout = (GridLayout)findViewById(R.id.root);
        for(int i = 0;i < chars.length;i++){
            Button bn = new Button(this);
            bn.setText(chars[i]);
            bn.setTextSize(40);
            bn.setPadding(5,35,5,35);
            GridLayout.Spec rowSpec = GridLayout.spec(i/4 + 2);
            GridLayout.Spec columnSpec = GridLayout.spec(i%4);
            GridLayout.LayoutParams params = new GridLayout.LayoutParams(rowSpec,columnSpec);
            params.setGravity(Gravity.FILL);
            gridLayout.addView(bn,params);

        }
    }
}

效果：