@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.welcome);
/**
* 延遲3秒進入主界面
*/
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
Intent intent=new Intent(WelcomeActivity.this,LoginActivity.class);
startActivity(intent);
WelcomeActivity.this.finish();
}
},1000*3);
}
}
public class LoginActivity extends Activity{
SharedPreferences sprfMain;
SharedPreferences.Editor editorMain;
Button login;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//在加載布局文件前判斷是否登陸過
sprfMain= PreferenceManager.getDefaultSharedPreferences(this);
editorMain=sprfMain.edit();
//.getBoolean("main",false)；當找不到"main"所對應的鍵值是默認返回false
if(sprfMain.getBoolean("main",false)){
Intent intent=new Intent(LoginActivity.this,MainActivity.class);
startActivity(intent);
LoginActivity.this.finish();
}
setContentView(R.layout.login);
login= (Button) findViewById(R.id.login);
//這裏只是簡單用按鍵模擬登錄功能
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent=new Intent(LoginActivity.this,MainActivity.class);
editorMain.putBoolean("main",true);
editorMain.commit();
startActivity(intent);
LoginActivity.this.finish();
}
});
}
}
public class MainActivity extends AppCompatActivity {
SharedPreferences sprfMain;
SharedPreferences.Editor editorMain;
Button exit;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
exit= (Button) findViewById(R.id.exit);
exit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//點擊註銷按鍵後調用LoginActivity提供的resetSprfMain()方法執行editorMain.putBoolean("main",false);，即將"main"對應的值修改為false
resetSprfMain();
Intent intent=new Intent(MainActivity.this,WelcomeActivity.class);
startActivity(intent);
MainActivity.this.finish();
}
});
}
public void resetSprfMain(){
sprfMain= PreferenceManager.getDefaultSharedPreferences(this);
editorMain=sprfMain.edit();
editorMain.putBoolean("main",false);
editorMain.commit();
}
}