自动完成预测后不切换活动

Question

当我进入＆＃34; Joh＆＃34;时，我得到了约翰肯尼迪＆＃34;。现在，当我点击＆＃34; John F. Kennedy＆＃34;时，它并没有带我去另一个提供John F. Kennedy信息的活动。但我已经编程了这样做。我的代码出了什么问题？

package com.mavenmaverick.autocomplete_test;

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Toast;
import android.view.inputmethod.InputMethodManager;


public class MainActivity extends Activity {

String[] presidents= {
                    "John F. Kennedy",
                    "Lyndon B. Johnson",
                    "Richard Nixon",
                    "Gerald Ford",
                    "Jimmy Carter",
                    "Ronald Reagan",
                    "George H. W. Bush",
                    "Bill Clinton",
                    "George W. Bush",
                    "Barack Obama"
                    };

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

    AutoCompleteTextView textView = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView1);
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.select_dialog_item, presidents);

    textView.setThreshold(3);
    textView.setAdapter(adapter);
    textView.setOnItemSelectedListener((OnItemSelectedListener) this);
    textView.setOnItemClickListener((OnItemClickListener) this);


    textView.setOnItemSelectedListener(new OnItemSelectedListener()
    {   
    @Override
    public void onItemSelected(AdapterView<?> parent, View view,
                   int index, long id)
    {
        int position=0;
        if(position == 1){
            Intent i = new Intent (MainActivity.this, SecondActivity.class);
            startActivity(i);
            }
    }
    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }
   });

    }
}

Answer 1

主要问题如下：

@Override
public void onItemSelected(AdapterView<?> parent, View view, int index, long id)
{
    int position=0;

    // once the logic reaches this part, the value
    // of "position" will always be 0 because that 
    // is what you are setting it too. Therefore, 
    // the following if statement is skipped.
    if(position == 1) {
        Intent i = new Intent (MainActivity.this, SecondActivity.class);
        startActivity(i);
    }
}

您想要改变它：

@Override
public void onItemSelected(AdapterView<?> parent, View view, int index, long id)
{
    if(position == 1) {
        Intent i = new Intent (MainActivity.this, SecondActivity.class);
        i.putExtra("KEY", presidents[index]);
        startActivity(i);
    }
}

putExtra方法用于在MainActivity和SecondActivity之间传递信息。它所采用的第一个参数是String用作键，第二个参数是实际值。

"KEY"可以是任何值，只需记住您将在SecondActivity中使用相同的键来获取值。例如：

String presidentClickedOn = getIntent().getStringExtra("KEY");