<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/main_layout" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_marginTop="100dp" android:text="点击按钮改变背景颜色" /> <Button android:id="@+id/button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:text="Button" /> </RelativeLayout>
package cn.itcase.backcolor; import androidx.appcompat.app.AlertDialog; import androidx.appcompat.app.AppCompatActivity; import android.content.DialogInterface; import android.graphics.Color; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.RelativeLayout; public class MainActivity extends AppCompatActivity implements View.OnClickListener { private Button button; int textSize=1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button=(Button)findViewById(R.id.button); button.setOnClickListener(this); } @Override public void onClick(View view) { AlertDialog dialog; AlertDialog.Builder builder = new AlertDialog.Builder(this) .setTitle("设置背景颜色") //设置标题 .setIcon(R.drawable.ic_launcher) .setSingleChoiceItems(new String[]{"红色", "白色", "黑色", "蓝色", "黄色"},textSize,new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { if (which==0){ ((RelativeLayout)findViewById(R.id.main_layout)).setBackgroundColor(Color.parseColor("#ff0000")); } else if(which==1){ ((RelativeLayout)findViewById(R.id.main_layout)).setBackgroundColor(Color.parseColor("#ffffff")); } else if(which==2){ ((RelativeLayout)findViewById(R.id.main_layout)).setBackgroundColor(Color.parseColor("#000000")); } else if(which==3){ ((RelativeLayout)findViewById(R.id.main_layout)).setBackgroundColor(Color.parseColor("#0000fb")); } else { ((RelativeLayout)findViewById(R.id.main_layout)).setBackgroundColor(Color.parseColor("#f1ff00")); } } }) .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // ((RelativeLayout)findViewById(R.id.main_layout)).setBackgroundColor(Color.parseColor("#3FE2C5")); dialog.dismiss(); } })//添加“确定”按钮 .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); dialog = builder.create(); dialog.show(); } }