Android中启动其他Activity并返回结果
启动其他Activity的一种常用方式就是StartActivity(),但有时候我们期望获取指定Activity返回的结果。这时，就需要使用startActivityForResult()方法，为了获取被启动的 Activity所返回的结果，当前Activity需要重写onActivityResult(int requestCode,int resultCode,Intent intent),其中requestCode代表请求码，resultCode代表返回的结果码，它们都是开发者根据业务自行设定的。这样就可以通过请求码和结果码来判断请求是由谁发出的，结果是由谁返回的。下面通过一个实例来演示：
第一个Activity：
import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; public class MainActivity extends Activity { Button btn; EditText city; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); city = (EditText) findViewById(R.id.activity_main_et); btn = (Button) findViewById(R.id.activity_main_btn); btn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // 创建需要对应于目标Activity的Intent Intent intent = new Intent(MainActivity.this, SelectCityActivity.class); // 启动指定Activity并等待返回的结果，其中0是请求码，用于标识该请求 startActivityForResult(intent, 0); } }); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == 0 && resultCode == 0) { // 取出Intent里的数据 String resultCity = data.getStringExtra("city"); // 修改city文本框的内容 city.setText(resultCity); } } }
第二个Activity：
import android.app.ExpandableListActivity; import android.content.Intent; import android.os.Bundle; import android.view.Gravity; import android.view.View; import android.view.ViewGroup; import android.widget.AbsListView; import android.widget.BaseExpandableListAdapter; import android.widget.ExpandableListAdapter; import android.widget.ExpandableListView; import android.widget.ExpandableListView.OnChildClickListener; import android.widget.LinearLayout; import android.widget.TextView; public class SelectCityActivity extends ExpandableListActivity { // 定义省份数组 private String[] provinces = new String[] { "广东", "广西", "湖南", "四川" }; // 定义各省份的城市数组 private String[][] cities = new String[][] { { "广州", "深圳", "珠海", "中山" }, { "桂林", "柳州", "南宁", "北海" }, { "长沙", "岳阳", "衡阳", "株洲" }, { "成都", "绵阳", "广安", "雅安" }, }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // 创建一个可展开的列表组件ExpandableListAdapter对象 ExpandableListAdapter adapter = new BaseExpandableListAdapter() { @Override public boolean isChildSelectable(int groupPosition, int childPosition) { return true; } @Override public boolean hasStableIds() { return true; } // 构建每个父列表组件 @Override public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { // 创建一个LinearLayout对象 LinearLayout ll = new LinearLayout(SelectCityActivity.this); ll.setOrientation(0); TextView textView = getTextView(); // 根据groupPosition取provinces对应文本作为textView显示的文本内容 textView.setText(getGroup(groupPosition).toString()); ll.addView(textView); return ll; } @Override public long getGroupId(int groupPosition) { return groupPosition; } @Override public int getGroupCount() { return provinces.length; } @Override public Object getGroup(int groupPosition) { return provinces[groupPosition]; } @Override public int getChildrenCount(int groupPosition) { return cities[groupPosition].length; } /** * 在MainActivity里创建TextView组件 * * @return TextView */ private TextView getTextView() { AbsListView.LayoutParams lp = new AbsListView.LayoutParams( ViewGroup.LayoutParams.MATCH_PARENT, 64); TextView textView = new TextView(SelectCityActivity.this); textView.setLayoutParams(lp); textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT); textView.setPadding(36, 0, 0, 0); textView.setTextSize(20); return textView; } // 构建子列表的数据 @Override public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) { TextView textView = getTextView(); // 根据groupPosition和childPosition取cities中对应文本作为textView显示的内容 textView.setText(getChild(groupPosition, childPosition) .toString()); return textView; } @Override public long getChildId(int groupPosition, int childPosition) { return childPosition; } @Override public Object getChild(int groupPosition, int childPosition) { return cities[groupPosition][childPosition]; } }; setListAdapter(adapter); // 为各个子列表绑定事件监听器 this.getExpandableListView().setOnChildClickListener( new OnChildClickListener() { @Override public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { Intent intent = getIntent(); Bundle data = new Bundle(); data.putString("city", cities[groupPosition][childPosition]); intent.putExtras(data); // 设置该SelectCityActivity结果码，并设置结束之后退回的Activity SelectCityActivity.this.setResult(0, intent); // 结束SelectCityActivity SelectCityActivity.this.finish(); return false; } }); } } 本文由用户 jopen 自行上传分享，仅供网友学习交流。所有权归原作者，若您的权利被侵害，请联系管理员。
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