安卓開發之鎖機軟件

package com.lidaochen.test03;

import android.app.ActivityManager;
import android.content.Intent;
import android.content.IntentFilter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private EditText et_pwd;
    private HomeReceiver innerReceiver;

    // 下面的函數 是屏蔽掉返回鍵
    @Override
    public void onBackPressed() {
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // 找到 EditText 控件
        et_pwd = (EditText)findViewById(R.id.et_pwd);
        // 動態註冊廣播接收者
        innerReceiver = new HomeReceiver();
        // 建立 IntentFilter 對象
        IntentFilter intentFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
        // 註冊廣播接收者
        registerReceiver(innerReceiver, intentFilter);
    }

    // 這個函數主要是爲了 屏蔽掉 recent APPS 按鍵
    @Override
    protected void onPause() {
        super.onPause();
        for (int j = 0; j < 50; j++){
            ActivityManager activityManager = (ActivityManager) getApplicationContext().getSystemService(this.ACTIVITY_SERVICE);
            activityManager.moveTaskToFront(getTaskId(), 0);
        }
    }

    // 密碼驗證按鈕點擊事件處理函數
    public void click(View v)
    {
        // 獲取用戶輸入的密碼
        String pwd = et_pwd.getText().toString().trim();
        if (pwd.equals("123456"))
        {
            Toast.makeText(getApplicationContext(), "密碼正確！", Toast.LENGTH_SHORT).show();
            System.exit(0);
        }
        else
        {
            Toast.makeText(getApplicationContext(), "密碼錯誤！", Toast.LENGTH_SHORT).show();
        }
    }
}

package com.lidaochen.test03;

import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class HomeReceiver extends BroadcastReceiver {
    static public final String SYSTEM_DIALOG_REASON_KEY = "reason";
    static public final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions";
    static public final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps";
    static public final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";
    static public final String SYSTEM_DIALOG_REASON_ASSIST = "assist";

    @Override
    public void onReceive(Context arg0, Intent arg1) {
        String action = arg1.getAction();
        // 按下Home鍵會發送 ACTION_CLOSE_SYSTEM_DIALOGS的廣播
        if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
            String reason = arg1.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
            if (reason != null) {
                if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) {
                    Intent intent = new Intent(arg0, MainActivity.class);
                    // 點擊home鍵無延時，且不會產生新的activity
                    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);
                    PendingIntent pendingIntent = PendingIntent.getActivity(arg0, 0, intent, 0);
                    try
                    {
                        pendingIntent.send();
                    }
                    catch (PendingIntent.CanceledException e)
                    {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    tools:context=".MainActivity">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="解鎖請加qq:1304168666"
        android:textColor="#ffff0f00"/>
    <EditText
        android:layout_width="250dp"
        android:layout_height="wrap_content"
        android:hint="請輸入密碼..."
        android:textColorHint="#ff9b05ff"
        android:textColor="#ff0006ff"
        android:layout_marginTop="30dp"
        android:lines="1"
        android:inputType="text"
        android:id="@+id/et_pwd"/>
    <Button
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:text="肯定"
        android:onClick="click"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="30dp"
        android:text="技術支持：李道臣"/>
</LinearLayout>參考連接：https://blog.csdn.net/qq_37820491/article/details/80940582