Intent之学习二（Activity间数据的传递）

2024-06-16 12:15| 来源: 网络整理| 查看: 265

Activity的启动常常有两种方式：startActivity()与startActivityForResult()。接下来，就以这两种方式为例讲解使用Intent在Activity间进行数据的传递。

1、startActivity()2、startActivityForResult() 1、startActivity()

用到的函数：startActivity(Intent intent)

从FirstActivity点击button1启动SecondActivity，在SecondActivity使用Log方式查看Intent传递的数据。

代码段

FirstActivity.class

SecondActivity.class

Intent intent = getIntent(); int data = intent.getIntExtra("ExtraData",-1); Log.d("SecondActivity",Integer.toString(data)); 2、startActivityForResult()

用到的函数： startActivityForResult(Intent intent, int requestCode) setResult(int resultCode,Intent intent) onActivityResult(int requestCode,int resultCode,Intent data)

从FirstActivity点击button1启动SecondActivity，并将Intent附带数据传给SecondActivity，在SecondActivity使用Log方式查看传递的数据。从FirstActivity点击button3启动ThirdActivity,此处Intent没有附带数据。分别从SecondActivity与ThirdActivity点击返回按键回到FirstActivity，并将Intent附带数据用Log方式打印出来。

代码段

FirstActivity.class

Button button1 = (Button)findViewById(R.id.button1); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(FirstActivity.this, SecondActivity.class); int data = 1; intent.putExtra("ExtraData", data); startActivityForResult(intent,2); } }); //隐式intent启动activity3 Button button3 = (Button)findViewById(R.id.button3); button3.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent("com.example.test.ACTION_START"); intent.addCategory("com.example.test.MY_CATEGORY"); startActivityForResult(intent, 3); } }); @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode){ case 2: if (resultCode==RESULT_OK){ String return_data = data.getStringExtra("return"); Log.d("FirstActivity",return_data); } case 3: if (resultCode==RESULT_OK){ String return_data = data.getStringExtra("return"); Log.d("FirstActivity",return_data); } } }

SecondActivity.class

Intent intent = getIntent(); int data = intent.getIntExtra("ExtraData",-1); Log.d("SecondActivity", Integer.toString(data)); @Override public void onBackPressed() { Intent intent = new Intent(); intent.putExtra("return","Second_to_First"); setResult(RESULT_OK,intent); finish(); }

ThirdActivity.class

@Override public void onBackPressed() { Intent intent = new Intent(); intent.putExtra("return", "Third_to_First"); setResult(RESULT_OK, intent); finish(); }

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