Button button = (Button) findViewById(R.id.writeButton);

        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                setContentView(R.layout.activity_write);
                Intent intent = new Intent(MainActivity.this,WriteActivity.class);
                startActivity(intent);
            }
        });		
		
			

四种 Activity 切换方式

		
    Intent intent = new Intent(MainActivity.this,HomeActivity.class);
    startActivity(intent);

    Intent intent = new Intent();
    intent.setClass(MainActivity.this,HomeActivity.class);
    startActivity(intent);

    Intent intent = new Intent();
    ComponentName componentName = new ComponentName(MainActivity.this,HomeActivity.class);
    intent.setComponent(componentName);
    startActivity(intent);


	startActivity(new Intent(MainActivity.this,HomeActivity.class));
		
		
		

		
    Intent intent = new Intent(Intent.ACTION_MAIN);
    //前提：知道要跳转应用的包名、类名
    ComponentName componentName = new ComponentName("cn.netkiller.album.hotel", "cn.netkiller.album.hotel.MainActivity");
    intent.setComponent(componentName);
    startActivity(intent);
		
			

		
// 定义跳转
ActivityResultLauncher<Intent> intentActivityResultLauncher =
        registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {
    Intent data = result.getData();
    if (result.getResultCode() == RESULT_OK && data != null) {
       // 一些逻辑
    }

});
                
// 使用时
Intent intent = new Intent(this,跳转到的.class);

// 执行跳转
intentActivityResultLauncher.launch(intent);		
		
			

startActivityForResult 即将废弃

		
    private void dispatchTakePictureIntent() {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        try {
            startActivityForResult(takePictureIntent, 1);
        } catch (ActivityNotFoundException e) {
            // display error state to the user
        }
    }		
		
			

替代方案是

		
   //拍照
    private final ActivityResultLauncher<Void> mLauncherCamera = registerForActivityResult(
    new ActivityResultContracts.TakePicturePreview(), result -> {
        //result为拍摄照片Bitmap格式
    });

    //开启拍照, 返回结果Bitmap
    private void launchCamera() {
        mLauncherCamera.launch(null);
    }		
		
			

			
package cn.netkiller;
 
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
 
public class SubActivity extends Activity{
	private TextView tv1;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		this.setContentView(R.layout.sub);
		tv1 = (TextView)this.findViewById(R.id.tv1);
		Intent intent = new Intent(); 
		intent.putExtra("response", "返回码为200");
		setResult(200,intent); 
		finish();
	}
 
}

			
			
				

		
package cn.netkiller;
 
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
 
public class IntentActivity extends Activity {
	private Button btn1;
	private TextView tv1;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn1 = (Button)this.findViewById(R.id.brn1);
        tv1 = (TextView)this.findViewById(R.id.tv2);
        btn1.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				Intent intent = new Intent();
				intent.setClass(IntentActivity.this, SubActivity.class);
				startActivityForResult(intent, 100); //requestcode=100
				
			}
		});
    }
    //回调函数，会根据requesrCode进行不同的响应
	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		super.onActivityResult(requestCode, resultCode, data);
		if(requestCode==100){
			// TODO: 响应逻辑
		}
		if(resultCode==200){
			Bundle bundle = data.getExtras();
			String response = bundle.getString("response");
			tv1.setText(response);
		}
	}
    
}