我的应用程序中有四个 Activity A-->B-->C-->D。
我写了一个扩展 Activity 类的我自己的类 MyActivity。我写这个类来处理 Activity 堆栈。这个类有两个方法 addActivitiyTostack() 和 getActivityFromStack() 我使用堆栈来存储 Activity 。
所有其他 Activity 都扩展了此类。 当我使用 Intent 从一项 Activity 转移到另一项 Activity 时，它会添加到堆栈中。
当我移动后退词时， Activity 会弹出。 我可以正确地将 Activity 添加到堆栈，但我在弹出 Activity 时遇到问题。
另外，我在所有 Activity 上都有注销按钮，这个按钮的 OnClick 我想关闭应用程序如何实现呢？任何人都知道如何在 Android 中处理 Activity 堆栈。
这是我的代码。
package com.example.iprotect;
import java.util.Enumeration;
import java.util.Stack;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
public class MyActivity extends Activity {
private static Stack<Activity> stack = new Stack<Activity>();
static int top=0;
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
addActivityToStack(this);
}
public static void addActivityToStack(MyActivity myActivity) {
// TODO Auto-generated method stub
stack.push(myActivity);
for (int i =0; i< stack.size() ; i++) {
Activity act=stack.get(i);
Log.i("Element in stack", ""+act);
}
}
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
//getActivityFromStack();
//logoutFromApplication();
}
public static void logoutFromApplication() {
// TODO Auto-generated method stub
Enumeration<Activity> enm=stack.elements();
while(enm.hasMoreElements())
{
Activity act=enm.nextElement();
stack.pop();
}
}
public static Activity getActivityFromStack() {
return stack.pop();
}
}
A-->
public class WebServiceActivity extends MyActivity{
EditText editText1, editText2;
Button button;
String response = "";
String email, password;
public final Pattern EMAIL_ADDRESS_PATTERN = Pattern
.compile(".+@.+\\.[a-z]+");
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText editText1 = (EditText) findViewById(R.id.etEmail);
final EditText editText2 = (EditText) findViewById(R.id.etPassword);
button = (Button) findViewById(R.id.loginButton);
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (TextUtils.isEmpty(editText1.getText().toString())) {
Toast.makeText(getApplicationContext(),
"please enter email id", Toast.LENGTH_SHORT).show();
} else if (TextUtils.isEmpty(editText2.getText().toString())) {
Toast.makeText(getApplicationContext(),
"please enter passwod", Toast.LENGTH_SHORT).show();
} else {
Boolean bool = EMAIL_ADDRESS_PATTERN.matcher(
editText1.getText().toString()).matches();
if (bool == true) {
} else {
Toast.makeText(getApplicationContext(),
"Invalid email id", Toast.LENGTH_SHORT).show();
}
email = editText1.getText().toString();
password = editText2.getText().toString();
// final ProgressDialog pd = ProgressDialog.show(
// WebServiceActivity.this, "Calling webservice...",
// "Please wait...", true, false);
final ProgressBar bar = (ProgressBar) findViewById(R.id.progressBar2);
bar.setVisibility(View.VISIBLE);
new AsyncTask<Void, Void, Void>() {
String r;
protected void onPreExecute() {
};
@Override
protected Void doInBackground(Void... params) {
r = invokeWebService();
return null;
};
protected void onPostExecute(Void result) {
bar.setVisibility(View.VISIBLE);
};
}.execute();
}
}
private String invokeWebService() {
String response = "";
try {
WebService webService = new WebService(
"http://sphinx-solution.com/iProtect/api.php?");
Map<String, String> params = new HashMap<String, String>();
params.put("action", "auth");
params.put("email", email);
params.put("password", password);
response = webService.WebGet("auth", params);
JSONObject jsonObject = new JSONObject(response);
String rr = jsonObject.optString("status");
if (TextUtils.equals(rr, "success")) {
Log.e("MSG", "status==success");
Intent intent = new Intent(WebServiceActivity.this,
SecondActivity.class);
//MyActivity.addActivityToStack(WebServiceActivity.this);
intent.putExtra("email", email);
intent.putExtra("password", password);
WebServiceActivity.this.startActivity(intent);
finish();
} else {
Log.e("MSG", "status ==failed");
}
} catch (Exception e) {
e.printStackTrace();
}
return response;
}
});
}
}
B-->
public class SecondActivity extends MyActivity {
ListView listView;
String email1, password1;
ArrayList<JSONStructure> arrayList = new ArrayList<JSONStructure>();
String r;
String r1;
String tablename;
String rows;
JSONObject jsonObject;
String tablename2;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second_layout);
Intent intent = getIntent();
email1 = intent.getExtras().getString("email");
password1 = intent.getExtras().getString("password");
Button btn1 = (Button) findViewById(R.id.refreshbutton);
btn1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
final ProgressDialog pd = ProgressDialog.show(
SecondActivity.this, "Refresh List...",
"Please wait...", true, false);
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
pd.dismiss();
r = invokeWebService();
return null;
}
protected void onPostExecute(Void result) {
};
}.execute();
}
});
Button btn = (Button) findViewById(R.id.logoutbutton);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
final ProgressDialog pd = ProgressDialog.show(
SecondActivity.this, "Calling webservice...",
"Please wait...", true, false);
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
pd.dismiss();
return null;
}
@Override
protected void onPostExecute(Void result) {
Intent intent = new Intent(SecondActivity.this,
WebServiceActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
SecondActivity.this.startActivity(intent);
}
}.execute();
}
});
listView = (ListView) findViewById(R.id.listview1);
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view,
int position, long id) {
JSONStructure jsonstructure = (JSONStructure) listView
.getAdapter().getItem(position);
final String tablename1 = jsonstructure.getTableName()
.toString();
Intent intent = new Intent(SecondActivity.this,
ProgressBarActivity.class);
//MyActivity.addActivityToStack(SecondActivity.this);
intent.putExtra("tablename", tablename1);
intent.putExtra("Rows", rows);
intent.putExtra("email", email1);
intent.putExtra("password", password1);
SecondActivity.this.startActivity(intent);
}
});
new AsyncTask<Void, Void, Void>() {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... params) {
r = invokeWebService();
try {
JSONArray jsonArray = new JSONArray();
JSONObject jsonObject = new JSONObject(r);
jsonArray = jsonObject.getJSONArray("Records");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject c = jsonArray.getJSONObject(i);
tablename = c.optString("TABLE NAME");
rows = c.optString("Rows");
JSONStructure jsonStructure = new JSONStructure();
jsonStructure.setTableName(tablename);
jsonStructure.setRows(rows);
arrayList.add(jsonStructure);
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
if (arrayList != null && arrayList.size() > 0) {
MyAdapter adapter = new MyAdapter(SecondActivity.this,
arrayList);
listView.setAdapter(adapter);
}
}
}.execute();
}
private String invokeWebService() {
String response = "";
try {
WebService webService = new WebService(
"http://sphinx-solution.com/iProtect/api.php?");
Map<String, String> params = new HashMap<String, String>();
params.put("action", "getTables");
params.put("email", email1);
params.put("password", password1);
response = webService.WebGet("getTables", params);
} catch (Exception e) {
e.printStackTrace();
}
return response;
}
}
C-->
public class ThirdActivity extends MyActivity {
String tablename1, row1, json1;
ArrayList<JSONStructure> arrayList = new ArrayList<JSONStructure>();
JSONArray jsonArray, jsonArray2;
JSONObject jsonObject;
String row;
String email1, password1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.third_layout);
ListView listView = (ListView) findViewById(R.id.listview2);
TextView textView = (TextView) findViewById(R.id.title_textview);
Intent intent = getIntent();
tablename1 = intent.getExtras().getString("tablename");
row = intent.getExtras().getString("Rows");
textView.setText(tablename1);
json1 = intent.getExtras().getString("Json");
email1 = intent.getExtras().getString("email");
password1 = intent.getExtras().getString("password");
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
return null;
}
@Override
protected void onPostExecute(Void result) {
Button button = (Button) findViewById(R.id.goback);
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(ThirdActivity.this,
SecondActivity.class);
MyActivity.getActivityFromStack();
intent.putExtra("email", email1);
intent.putExtra("password", password1);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
ThirdActivity.this.startActivity(intent);
}
});
}
}.execute();
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view,
final int position, long id) {
final ProgressDialog pd = ProgressDialog.show(
ThirdActivity.this, "Calling webservice...",
"Please wait...", true, false);
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... paramArrayOfParams) {
pd.dismiss();
try {
jsonObject = new JSONObject(json1);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
Intent intent = new Intent(ThirdActivity.this,
FinalActivity.class);
//MyActivity.addActivityToStack(ThirdActivity.this);
intent.putExtra("tablename", tablename1);
intent.putExtra("Json", jsonObject.toString());
intent.putExtra("Row", position);
intent.putExtra("email", email1);
intent.putExtra("password", password1);
ThirdActivity.this.startActivity(intent);
}
}.execute();
}
});
try {
JSONObject jsonObject = new JSONObject(json1);
JSONArray jsonArray = new JSONArray();
jsonArray = jsonObject.getJSONArray("FirstThree");
jsonArray2 = jsonObject.getJSONArray("Color");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject c = jsonArray.getJSONObject(i);
String one = c.optString("One");
String two = c.optString("Two");
String three = c.optString("Three");
JSONObject c1 = jsonArray2.getJSONObject(i);
String color = c1.optString("color");
JSONStructure jsonStructure = new JSONStructure();
jsonStructure.column1 = one;
jsonStructure.column2 = two;
jsonStructure.column3 = three;
jsonStructure.setColumn1(one);
jsonStructure.setColumn2(two);
jsonStructure.setColumn3(three);
jsonStructure.setColor(color);
arrayList.add(jsonStructure);
Log.e("one", c.optString("One"));
Log.e("two", c.optString("Two"));
Log.e("three", c.optString("Three"));
Log.e("color", c1.optString("color"));
}
} catch (Exception e) {
e.printStackTrace();
}
if (arrayList != null && arrayList.size() > 0) {
MyAdapter1 adapter1 = new MyAdapter1(ThirdActivity.this, arrayList);
listView.setAdapter(adapter1);
}
Button btn = (Button) findViewById(R.id.logoutbutton);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
final ProgressDialog pd = ProgressDialog.show(
ThirdActivity.this, "Calling webservice...",
"Please wait...", true, false);
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
pd.dismiss();
return null;
}
@Override
protected void onPostExecute(Void result) {
Intent intent = new Intent(ThirdActivity.this,
WebServiceActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
ThirdActivity.this.startActivity(intent);
super.onPostExecute(result);
}
}.execute();
}
});
}
}
最佳答案
假设您只需要此堆栈用于注销功能，则有更好的方法。请改用广播。在 MyActivity.onCreate 中注册一个 BroadcastReceiver。接收者应该只调用 Activity 的 finish()。从按钮的点击监听器发送广播(btn1？那个按钮有什么作用？无法从名称中猜出；需要更好的名称；))。就是这样。
关于android - 以编程方式通过应用程序处理 Activity 堆栈，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12562841/