如何開始需要活動，當我在文件中保存數據？

當應用程序首先啓動時，用兩個按鈕啓動Activity：創建文件和設置。然後，如果我點擊按鈕創建文件 - 啓動活動，我寫文本並保存在文件中。如果我們在保存文件時發生錯誤 - 使用兩個按鈕啓動活動。否則用三個按鈕啓動另一個活動：查看文件，編輯文件，設置。如何開始需要活動，當我在文件中保存數據？

如何組織這個活動和如何使用三個按鈕啓動活動（如果文件已保存）之間的正確轉換？

public class MainFirstActivity extends AppCompatActivity { 

private Button createFile; 
private Button settings; 
private boolean start = true; 

private static final String MY_SETTINGS = "my_settings"; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main_first); 

    createFile = (Button) findViewById(R.id.create_file); 
    settings = (Button) findViewById(R.id.settings); 



    createFile.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent intent = new Intent(MainFirstActivity.this, CreateFileActivity.class); 
      startActivity(intent); 
      // MainFirstActivity.this.finish(); 
     } 
    }); 

    settings.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent intent = new Intent(MainFirstActivity.this, SettingActivity.class); 
      startActivity(intent); 
     } 
    }); 
} 

@Override 
protected void onResume() { 
    super.onResume(); 

    File f = new File(CreateFileActivity.FILE_NAME); 
    if(!f.exists() && !f.isDirectory() && start) { 
     Intent intent = new Intent(MainFirstActivity.this, MainWithFileActivity.class); 
     startActivity(intent); 
     //start=false; 
     MainFirstActivity.this.finish(); 
     Log.e("err", "intent"); 
    } 
} 
}

MainWithFileActivity

public class MainWithFileActivity extends AppCompatActivity { 

public static final String MY_SETTINGS = "MY_SETTINGS"; 

private Button lookFile; 
private Button editFile; 
private Button settings; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main_if_first); 

    lookFile = (Button) findViewById(R.id.look_file); 
    settings = (Button) findViewById(R.id.settings); 
    editFile = (Button) findViewById(R.id.edit_file); 

    lookFile.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent intent = new Intent(MainWithFileActivity.this, LookFileActivity.class); 
      startActivity(intent); 
     } 
    }); 

    editFile.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent intent = new Intent(MainWithFileActivity.this,CreateFileActivity.class); 
      startActivity(intent); 
     } 
    }); 

    settings.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent intent = new Intent(MainWithFileActivity.this, SettingActivity.class); 
      startActivity(intent); 
     } 
    }); 

} 
}

來源

2016-02-12 Yahor Urbanovich

只需檢查文件是否存在。如果沒有，隱藏lookFile按鈕

在MainWithFileActivityonCreate方法添加此

File f = new File(CreateFileActivity.FILE_NAME); 
if(!f.exists() && !f.isDirectory()) { 
    lookFile.setVisibility(View.GONE); 
}

來源

2016-02-12 12:45:54 Rohit5k2

如何開始需要活動，當我在文件中保存數據？

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