android---Activity間消息互傳

當一個Activity1開啟一個新的Activity2時，可以將一個Bundle對象綁定在Intent中進行傳遞，而Bundle對象中可以存儲很多種類型的數據，支持的數據類型有int、string、ArrayList、List、boolean、byte、char等等，如果關閉Activity2返回Activity1時要傳遞數據，則Activity1需以startActivityForResult(intent,requestCode)方式開啟Activity2,並且Axtivity2設置setResult(RESULT_OK, intent)，這樣當關閉Activity2時，就會觸發Activity的回調函數onActivityResult();

完整代碼如下：

Activity1

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        btnjump=(Button)findViewById(R.id.btnload);
        btnjump.setOnClickListener(this);
        etname=(EditText)findViewById(R.id.actname);
        etpwd=(EditText)findViewById(R.id.etpwd);
        }
    
    //被此Activity啟動的Activity返回結果時觸發的回調函數
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data){
        if(resultCode==RESULT_OK){
            Bundle bundle=data.getExtras();
            Toast.makeText(this, bundle.getString("name")+"/"+bundle.getString("pwd"), Toast.LENGTH_LONG);
        }
        super.onActivityResult(requestCode, resultCode, data);
    }
    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        String name=etname.getText().toString();
        String pwd=etpwd.getText().toString();
        Intent intent = new Intent();
        Bundle bundle=new Bundle();
        bundle.putString("name", name);
        bundle.putString("pwd", pwd);
        intent.putExtras(bundle);
        
        //requestCode大於等於0,當返回Activity時，會回調onActivityResult()函數
        int requestCode=0;
        //啟動一個Activity，並且被啟動的Activity返回結果時會觸發回調函數
        this.startActivityForResult(intent,requestCode);
    }

Activity2:

public class TwoActivity extends Activity {

    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.two);
        TextView tvshow=(TextView)findViewById(R.id.tvShow);
        Intent intent= this.getIntent();
        Bundle bundle=intent.getExtras();
        final String name=bundle.getString("name");
        final String pwd=bundle.getString("pwd");
        tvshow.setText(name+"/"+pwd);
        
        Button btn=(Button)findViewById(R.id.btnback);
        btn.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent data=new Intent();
                Bundle extras = new Bundle();
                extras.putString("name","返回:"+name );
                extras.putString("pwd", "返回:"+pwd);
                data.putExtras(extras);
                TwoActivity.this.setResult(RESULT_OK, data);//返回數據
                finish();
            }
        });
    }
}