Java 当我将数据保存在文件中时，如何启动所需的活动？

当应用程序首先启动时，用两个按钮启动活动：创建文件和设置。然后，若我点击按钮Createfile-start活动，我将在其中写入文本并保存到文件中。 如果文件保存时出错-使用两个按钮启动活动。否则，用三个按钮启动另一个活动：查看文件、编辑文件、设置

如何组织此活动之间的正确转换，以及如果文件已保存，如何使用三个按钮启动活动

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);
        }
    });

}
}

---

只需检查文件是否存在。如果没有，则隐藏

lookFile

按钮

将此添加到

MainWithFileActivity

onCreate

方法中

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