如何从意图传递HashMap <String，List <String>>

Question

我在这里有一个代码，我想通过单击保存按钮来传递哈希映射函数。我看了Here，但找不到解决方案。

上点击按钮，我需要通过hasmap.Anyone请帮助this.My代码是：

btnsave = (Button) findViewById(R.id.btn_save); 
    btnsave.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 

      try { 
       expandableDataPump.getData(); 
       Intent intent = new Intent(getApplicationContext(), ExpandableList.class); 
//HERE I NEED TO PASS HASHMAP 
       intent.putStringArrayListExtra("details",(HashMap<String,>) expandableDataPump.getData()); 

       startActivity(intent); 
      } catch (Exception ex) { 
       ex.printStackTrace(); 

       Toast.makeText(MainActivity.this, "You have an ERROR", Toast.LENGTH_LONG).show(); 
      } 


     } 
    }); 

} 

public class ExpandableDataPump { 
    public HashMap<String, List<String>> getData() { 
     HashMap<String, List<String>> expandableListDetail = new HashMap<>(); 

     for (int i = 2; i < container.getChildCount(); i++) { 
      if (container.getChildAt(i) instanceof RelativeLayout) { 
       List<String> childs = new ArrayList<>(); 
       childs.add(((TextView)container.getChildAt(i).findViewById(R.id.textout)).getText().toString()); 
       expandableListDetail.put(txtHeading.getText().toString(), childs); 
      } 
     } 


     return expandableListDetail; 
    } 
} 

}

Answer 1

你做错了，一切都Collections序列化，为了通过HashMap的进入意图使用

putExtra(String key, Serializable obj) 

，并从意图获取数组回来，你做

getIntent().getSerializableExtra(String key) 

你的答案

btnsave = (Button) findViewById(R.id.btn_save); 
btnsave.setOnClickListener(new View.OnClickListener() { 
    @Override 
    public void onClick(View v) { 

     try { 
      Intent intent = new Intent(getApplicationContext(), S.class); 
      intent.putExtra("details", getData()); 

      startActivity(intent); 
     } catch (Exception ex) { 
      ex.printStackTrace(); 
      Toast.makeText(MainActivity.this, "You have an ERROR", Toast.LENGTH_LONG).show(); 
     } 


    } 
}); 

public HashMap< String, List<String> > getData() { 
    HashMap< String, List<String> > expandableListDetail = new HashMap<>(); 

    for (int i = 2 ; i < container.getChildCount() ; i++) { 
     if (container.getChildAt(i) instanceof RelativeLayout) { 
      List<String> childs = new ArrayList<>(); 
      childs.add(((TextView) container.getChildAt(i).findViewById(R.id.textout)).getText().toString()); 
      expandableListDetail.put(txtHeading.getText().toString(), childs); 
     } 
    } 
    return expandableListDetail; 
} 

Answer 2

使用

extras.putSerializable("HashMap",Hash_Map); 
intent.putExtras(extras); 

而不是

intent.putStringArrayListExtra（ “详细信息”，（HashMap的）expandableDataPump.getData（））;

btnsave = (Button) findViewById(R.id.btn_save); 
btnsave.setOnClickListener(new View.OnClickListener() { 
    @Override 
    public void onClick(View v) { 

     try { 
      expandableDataPump.getData(); 
      Intent intent = new Intent(getApplicationContext(), ExpandableList.class); 
      intent.putExtra("details",(HashMap<String,>) expandableDataPump.getData()); 

      startActivity(intent); 
     } catch (Exception ex) { 
      ex.printStackTrace(); 

      Toast.makeText(MainActivity.this, "You have an ERROR", Toast.LENGTH_LONG).show(); 
     } 


    } 
}); 

}

Answer 3

您可以通过以下只是下面的指令做到这一点。

首先使用实现Serializable创建类，如下所示。

public class DataWrapper implements Serializable{ 

    private HashMap<String,List<String>> hasmap; 

    public DataWrapper(HashMap<String,List<String>> hasmap){ 
     this.hasmap= hasmap; 
    } 

    public HashMap<String,List<String>> getHashMap(){ 
     return this.hasmap; 
    } 
} 

从你想要通过的活动HashMap<String,List<String>>把下面的代码。

DataWrapper dw = new DataWrapper(expandableDataPump.getData()); 

Intent intent = new Intent(getApplicationContext(), ExpandableList.class); 
intent.putExtra("details", dw); 
startActivity(intent); 

在你ExpandableList活动取得DataWrapper对象，如下图所示，从该对象检索您HashMap。

try{ 
    Intent intent = getIntent(); 
    DataWrapper dw = (DataWrapper) intent.getSerializableExtra("details"); 
    HashMap<String,List<String>> hasmap = dw.getHashMap(); 
} catch(Exception e){ 
} 

就是这样。它为我工作。

Answer 4

要通过HashMap，

btnsave.setOnClickListener(new View.OnClickListener() { 

    @Override 
    public void onClick(View v) { 

     try { 
      Intent intent = new Intent(getApplicationContext(), ExpandableList.class); 
      intent.putExtra("details", expandableDataPump.getData()); 
      startActivity(intent); 
     } catch (Exception ex) { 
      ex.printStackTrace(); 
     } 

    } 
}); 

要ExpandableList检索，

HashMap<String,List<String>> hashmap = (HashMap<String,List<String>>) getIntent().getSerializableExtra("details");