编写不易，如有转载，请声明出处：/zxc514257857/article/details/69219113
Demo效果展示如下：
布局代码如下：
//(layout)activity_main.xml<LinearLayoutxmlns:android="/apk/res/android"xmlns:tools="/tools"android:id="@+id/activity_main"android:layout_width="match_parent"android:layout_height="match_parent"tools:context="com.test.qqlogin.MainActivity"android:orientation="vertical"><RelativeLayoutandroid:layout_weight="1"android:background="#11B6F4"android:layout_width="match_parent"android:layout_height="0dp"><ImageViewandroid:src="@mipmap/pic"android:layout_centerInParent="true"android:layout_width="wrap_content"android:layout_height="wrap_content"/></RelativeLayout><RelativeLayoutandroid:gravity="center_horizontal"android:layout_weight="1"android:layout_width="match_parent"android:layout_height="0dp"><RelativeLayoutandroid:layout_centerInParent="true"android:layout_width="wrap_content"android:layout_height="wrap_content"><EditTextandroid:paddingLeft="10dp"android:id="@+id/et_username"android:layout_width="400dp"android:layout_height="30dp"android:background="@drawable/edittext_shape"android:singleLine="true"android:hint="QQ号码/手机/邮箱"/><EditTextandroid:layout_marginTop="5dp"android:paddingLeft="10dp"android:layout_below="@+id/et_username"android:id="@+id/et_password"android:inputType="textPassword"android:layout_width="400dp"android:layout_height="30dp"android:background="@drawable/edittext_shape"android:singleLine="true"android:hint="密码"/><CheckBoxandroid:id="@+id/cb_savePassword"android:layout_marginTop="5dp"android:textSize="18sp"android:text="记住密码"android:layout_below="@+id/et_password"android:layout_width="wrap_content"android:layout_height="wrap_content"/><RelativeLayoutandroid:layout_below="@+id/cb_savePassword"android:layout_marginTop="5dp"android:layout_width="400dp"android:layout_height="30dp"><Buttonandroid:id="@+id/login"android:layout_width="180dp"android:layout_height="wrap_content"android:text="确 定"android:textSize="20sp"android:layout_alignParentLeft="true"android:background="@drawable/button_selector"android:textColor="#fff"android:onClick="login"/><Buttonandroid:id="@+id/logout"android:layout_width="180dp"android:layout_height="wrap_content"android:text="退 出"android:textSize="20sp"android:layout_alignParentRight="true"android:background="@drawable/button_selector"android:textColor="#fff"android:onClick="logout"/></RelativeLayout></RelativeLayout></RelativeLayout></LinearLayout>-----------------------------------------------------------//(layout)activity_second.xml<LinearLayout xmlns:android="/apk/res/android"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"><ImageViewandroid:background="@mipmap/p1"android:layout_width="match_parent"android:layout_height="match_parent"/></LinearLayout>-----------------------------------------------------------//(drawable)button_selector.xml<selector xmlns:android="/apk/res/android"><item android:state_pressed="true"><shape android:shape="rectangle"><corners android:radius="10px"/><solid android:color="@color/colorYellow"/><stroke android:width="1px" android:color="#FFF"/></shape></item><item android:state_pressed="false"><shape android:shape="rectangle"><corners android:radius="10px"/><solid android:color="@color/colorBlue"/><stroke android:width="1px" android:color="#FFF"/></shape></item><item android:state_selected="true"><shape android:shape="rectangle"><corners android:radius="10px"/><solid android:color="@color/colorYellow"/><stroke android:width="1px" android:color="#FFF"/></shape></item><item android:state_selected="false"><shape android:shape="rectangle"><corners android:radius="10px"/><solid android:color="@color/colorBlue"/><stroke android:width="1px" android:color="#FFF"/></shape></item></selector>-----------------------------------------------------------//(drawable)edittext_shape.xml<shape xmlns:android="/apk/res/android"><solid android:color="#fff"/><corners android:radius="8px"/><stroke android:color="#2BA6E1"android:width="2px"/></shape>
activity代码如下：
//MainActivityimport android.content.DialogInterface;import android.content.Intent;import android.content.pm.ActivityInfo;import android.os.Bundle;import android.support.v7.app.AlertDialog;import android.support.v7.app.AppCompatActivity;import android.text.InputType;import android.text.TextUtils;import android.util.Log;import android.view.View;import android.widget.CheckBox;import android.widget.EditText;import android.widget.Toast;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.InputStreamReader;public class MainActivity extends AppCompatActivity {private EditText mEt_username;private EditText mEt_password;private CheckBox mCb_savePassword;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//强制设置为横屏setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);initView();initData();exitActivity();}private void exitActivity() {ExitApplication.getInstance().addActivity(MainActivity.this);}private void initView(){mEt_username = (EditText) findViewById(R.id.et_username);mEt_password = (EditText) findViewById(R.id.et_password);//设置密码输入模式mEt_password.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);mCb_savePassword = (CheckBox) findViewById(R.id.cb_savePassword);}//进入程序 如果有缓存 就读取缓存的帐号密码private void initData(){//帐号密码保存在内存缓存中File file = new File(this.getCacheDir(),"QQLogin.txt");read(file);}private void read(File file) {//帐号密码保存在SDcard中//File file = new File(Environment.getExternalStorageDirectory(),"QQLogin.txt");if(file.exists() && file.length() > 0){try {//读流FileInputStream fis = new FileInputStream(file);BufferedReader br = new BufferedReader(new InputStreamReader(fis));String QQLogin = br.readLine();//帐号密码用##分隔，所以用##切割String username = QQLogin.split("##")[0];String password = QQLogin.split("##")[1];//并将缓存的帐号密码显现mEt_username.setText(username);mEt_password.setText(password);mCb_savePassword.setChecked(true);fis.close();br.close();} catch (Exception e) {e.printStackTrace();}}}public void login(View view) {String username = mEt_username.getText().toString().trim();String password = mEt_password.getText().toString().trim();if (TextUtils.isEmpty(username) || TextUtils.isEmpty(password)) {Toast.makeText(this, "帐号或密码为空，请重新输入！", Toast.LENGTH_SHORT).show();return;}if (username.equals("123456") && password.equals("123456")) {Intent intent = new Intent(MainActivity.this, SecondActivity.class);startActivity(intent);}checkAndWrite(username, password);}private void checkAndWrite(String username , String password) {if (mCb_savePassword.isChecked()) {Toast.makeText(this, "记住密码！", Toast.LENGTH_SHORT).show();//帐号密码保存在内存缓存中File file = new File(this.getCacheDir(),"QQLogin.txt");try {//写流FileOutputStream fos = new FileOutputStream(file);fos.write((username + "##" + password).getBytes());Toast.makeText(this, "数据保存成功", Toast.LENGTH_SHORT).show();fos.close();} catch (Exception e) {Toast.makeText(this, "数据保存失败", Toast.LENGTH_SHORT).show();e.printStackTrace();Log.i("Main", e.toString());}} else {Toast.makeText(this, "取消密码！", Toast.LENGTH_SHORT).show();File file = new File(this.getCacheDir(),"QQLogin.txt");if(file.exists() && file.length() > 0){file.delete();}}}//点击登录按钮public void logout(View view){needEnterPwd();}//点击返回按钮public void onBackPressed(){needEnterPwd();}//需输入密码private void needEnterPwd() {final EditText password = new EditText(this);password.setFocusable(true);//设置为密码不可见形式password.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);AlertDialog.Builder builder = new AlertDialog.Builder(this);builder.setTitle("请输入退出密码").setIcon(R.mipmap.ic_launcher).setNegativeButton("取消", null).setCancelable(false).setView(password).setPositiveButton("确定",new DialogInterface.OnClickListener() {public void onClick(DialogInterface dialog, int which) {String inputName = password.getText().toString();if(inputName.equals("123456")){//退出所有Activity操作ExitApplication.getInstance().exit();}else{new AlertDialog.Builder(MainActivity.this).setTitle("警告").setIcon(R.mipmap.ic_launcher).setMessage("密码输入错误,请重新输入!").setCancelable(false).setNegativeButton("取消",null).setPositiveButton("确定",null).show();}}}).show();}}-----------------------------------------------------------//SecondActivityimport android.content.pm.ActivityInfo;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;public class SecondActivity extends AppCompatActivity{@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_second);//强制设置为横屏setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);exitActivity();}private void exitActivity() {ExitApplication.getInstance().addActivity(SecondActivity.this);}}-----------------------------------------------------------//ExitApplicationimport android.app.Activity;import android.app.Application;import java.util.ArrayList;import java.util.List;public class ExitApplication extends Application {private List<Activity> activityList = new ArrayList<>();private static ExitApplication instance;public ExitApplication(){}public static ExitApplication getInstance(){if(null == instance){instance = new ExitApplication();}return instance;}//添加Activity到容器中public void addActivity(Activity activity){activityList.add(activity);}//遍历所有Activity并finishpublic void exit(){for(Activity activity : activityList){//依次关闭activity.finish();}//强制退出System.exit(0);}}
Demo下载请移步：/detail/zxc514257857/9833032
----------因本人才疏学浅，如博客或Demo中有错误的地方请大家随意指出，与大家一起讨论，共同进步，谢谢！----------
