Android通过点击按钮改变Activity的背景颜色_个人笔记

今天学习了通过两个按钮的点击监听事件。

private Button button1; 

private Button button2; 

private LinearLayout layout;

先声明按钮、布局LinearLayout

package com.example.cong.colorbutton;
import android.graphics.Color;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {
    private Button button1;
    private Button button2;
    private Button button3;
    private LinearLayout layout;
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button1= (Button) this.findViewById(R.id.button1);
        button2= (Button) this.findViewById(R.id.button2);
        button3= (Button) this.findViewById(R.id.button3);
        layout= (LinearLayout) this.findViewById(R.id.layout);

        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                layout.setBackgroundColor(Color.RED);

            }
        });

        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                layout.setBackgroundColor(Color.BLUE);

            }
        });
        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                layout.setBackgroundColor(Color.GREEN);

            }
        });
    }
}

以下是xml的代码

在这里需要注意的是要明确LinearLayout的ID

android:id=“@+id/layout”

实现出来就是点哪个按钮，背景就变什么色。

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