shared preferences是什么？就是數(shù)據(jù)的持久化，主要保存一些簡單的數(shù)據(jù)在應(yīng)用內(nèi)部
定義變量：

private Button mButton;
private boolean mDatas;

調(diào)用函數(shù)

@Override
protected void onCreate(Bundle savedInstanceState) {      
   super.onCreate(savedInstanceState); 
   setContentView(R.layout.activity_first);  
   setData();  
   saveDataPreference(mDatas);
}

private void setData() {
    SharedPreferences sharedPreferences =FirstActivity.this.getSharedPreferences("preference_name", Context.MODE_PRIVATE);
    mDatas = sharedPreferences.getBoolean("mData", true);
    if (mDatas == false) {
        startActivity(new Intent(FirstActivity.this, MainActivity.class));       
        finish();
} 
    else {
         mButton = (Button) findViewById(R.id.button1);
         mButton.setOnClickListener(new View.OnClickListener() {    ;           
    @Override    
              public void onClick(View view) {
              startActivity(new Intent(FirstActivity.this, SecondActivity.class));          
              FirstActivity.this.finish();
              }
     });

private void saveDataPreference(boolean data){
    //系統(tǒng)會(huì)自動(dòng)幫我們創(chuàng)建一個(gè)XML文件  名字是"preference_name "     
      SharedPreferences sharedPreferences = FirstActivity.this.getSharedPreferences("preference_name", Context.MODE_PRIVATE);
      SharedPreferences.Editor editor = sharedPreferences.edit();      
      editor.putBoolean("mData",false);
      editor.commit();
}