java - 如何使用 Intent 将用户输入数据从一个 Activity 发送到另一个 Activity

Question

下面的代码是第三个和第四个 Activity 的源代码。第三个 Activity 接收用户输入并对其执行数学运算。然后将原始值和处理后的值都发送到需要显示的第四个 Activity 。我不太熟悉 Intent 的使用。有人可以检查我的代码吗？它不起作用。

第三个 Activity

public class Third extends Activity {

double x=0, val1=0;


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

    final EditText et;
    final Button b;

    et = (EditText) findViewById(R.id.editText1);
    b = (Button) findViewById(R.id.button1);

    b.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            Intent intent = new Intent(Third.this, Fourth.class);
            intent.putExtra("thetext", et.getText().toString());
            startActivity(intent);

            x=Double.parseDouble(et.getText().toString());

            val1=(x*.04);

            Intent in1 = new Intent(Third.this, Fourth.class);
            in1.putExtra("thevalue1",val1);
            startActivity(in1);

        }


  });

}
}

第四个 Activity :

public class Fourth extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.fourth);

    TextView tv = (TextView) findViewById(R.id.textView1);
    tv.setText(getIntent().getExtras().getString("thetext"));


    TextView wt1=(TextView) findViewById(R.id.textView12);
    wt1.setText(getIntent().getExtras().getDouble("thevalue1"));
} 

}

Answer 1

您需要将两个附加项放入一个 Intent 中，并且只调用一次 startActivity(...)。更改第三个 Activity 的代码(在 onClick(...) 方法中)如下...

Intent intent = new Intent(Third.this, Fourth.class);
intent.putExtra("thetext", et.getText().toString());
x=Double.parseDouble(et.getText().toString());
val1=(x*.04);
intent.putExtra("thevalue1",val1);
startActivity(intent);