Android开发：绘制按纽

1 在/app/res/layout/下建立btn.xml，内容为：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <TextView android:id="@+id/textView1"
        android:text="show something"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
    </TextView>  

    <Button android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:background="@drawable/btnshape"
        android:textColor="#ff0000"
        android:alpha="0.5"
        android:text="Click Me!">
    </Button>
</RelativeLayout>

2 在/app/res/drawable/下建立btnshape.xml，内容为：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <corners android:radius="10dp"/>
    <solid android:color="#00ff00"/>
    <stroke android:color="#000000" android:width="2dp"/>
</shape>

3 在/app/java/com.example.z.helloworld/MainActivity中编辑代码

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    Button b1;
    TextView t1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
//        setContentView(R.layout.activity_main);
        setContentView(R.layout.btn);
        b1 = (Button)findViewById(R.id.button1);
        t1 = (TextView)findViewById(R.id.textView1);
        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                t1.setText(System.currentTimeMillis() + " Hello World!");
            }
        });
    }
}

4 工程目录如下图所示

5 运行结果