与主要活动发现意图的意图发现错误

Question

我是一个新手，正面临着意图问题。 目标：生成一个列表，然后单击“列表”中的一个项目，打开一个新布局，其中包含一些意向传递的参数。

问题：

1. 如果我尝试使用下面的代码，则会收到找不到该意图的错误。
2. 如果我尝试使用特定的intent组件（虚线），则会给出运行时异常消息，提示“您的内容必须具有id属性为'android.R.id.list'的listview。

请帮忙。

package com.example.testapp08;

import android.os.Bundle;
import android.view.View;
import android.app.ListActivity;
import android.content.Intent;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;


public class MainActivity extends ListActivity {
    String[]countries;
    final String THE_ACTION2 = "com.example.testapp08.TEMPT2";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        countries=getResources().getStringArray(R.array.countries);
        this.setListAdapter(new ArrayAdapter<String>(
                this, 
                R.layout.list_layout, 
                R.id.countryName, 
                countries));

        ListView listview = getListView();

        listview.setOnItemClickListener(new OnItemClickListener()
        {

            @Override
            public void onItemClick(AdapterView<?> parent, View clickView, int position,
                    long id) {
                // TODO Auto-generated method stub
                String country = countries[position];
                //Toast.makeText(MainActivity.this, String.format("%s was chosen", country), Toast.LENGTH_SHORT).show();
                //Intent intent = new Intent(MainActivity.this, Tempt1.class );
                Intent intent = new Intent();
                intent.setAction(THE_ACTION2);
                intent.putExtra("MY TEXT", country);
                startActivity(intent);
            }
        });

    }
}

---

package com.example.testapp08;


import android.os.Bundle;
import android.widget.TextView;

public class Tempt1 extends MainActivity{
        TextView textView1;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.temp_layout);
        textView1 = (TextView) findViewById(R.id.textView1);
        Bundle bundle = getIntent().getExtras();

        String var_from_prev_intent = bundle.getString("MY TEXT");
        textView1.setText(var_from_prev_intent);

}
}

Answer 1

我给你一个非常简单的listview的例子。

import android.os.Bundle;
import android.view.View;
import android.app.ListActivity;
import android.content.Intent;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;


public class MainActivity extends ListActivity {
    String[]countries;
    final String THE_ACTION2 = "com.example.testapp08.TEMPT2";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        countries=getResources().getStringArray(R.array.country);
        this.setListAdapter(new ArrayAdapter<String>(
                this, 
                android.R.layout.simple_list_item_1, 

                countries));

        ListView listview = getListView();

        listview.setOnItemClickListener(new OnItemClickListener()
        {

            @Override
            public void onItemClick(AdapterView<?> parent, View clickView, int position,
                    long id) {
                // TODO Auto-generated method stub
                String country = countries[position];
                //Toast.makeText(MainActivity.this, String.format("%s was chosen", country), Toast.LENGTH_SHORT).show();
                //Intent intent = new Intent(MainActivity.this, Tempt1.class );
                Intent intent = new Intent(MainActivity.this,MainActivity2.class);
                //intent.setAction(THE_ACTION2);
                intent.putExtra("MY TEXT", country);
                startActivity(intent);
            }
        });

    }
}

2）MainActivity2.java

import android.support.v7.app.ActionBarActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

public class MainActivity2 extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_activity2);
        Intent i = getIntent();
        Toast.makeText(this,i.getStringExtra("MY TEXT"), Toast.LENGTH_SHORT).show();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main_activity2, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

现在，当您单击任何列表项时，您将看到以toast msg格式选择的内容。

希望这会帮助你。