在不同Activity之间传递数据的四种常用方法
在Android中传递数据的方法非常多,本次介绍4中比较常用的数据传递方法:
1.通过Intent传递数据
2.通过静态变量(static)传递数据
3.通过剪贴板(Clipboard)传递数据
4.通过全局对象传递数据
在TransmitDataActivity.java中
packagemobile.android.transmit.data; publicclassTransmitDataActivityextendsActivity{ @Override protectedvoidonCreate(BundlesavedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.main); Buttonbutton1=(Button)findViewById(R.id.button1); Buttonbutton2=(Button)findViewById(R.id.button2); Buttonbutton3=(Button)findViewById(R.id.button3); Buttonbutton4=(Button)findViewById(R.id.button4); button1.setOnClickListener(newButtonListenner()); button2.setOnClickListener(newButtonListenner()); button3.setOnClickListener(newButtonListenner()); button4.setOnClickListener(newButtonListenner()); } classButtonListennerimplementsOnClickListener{ @SuppressLint("NewApi") @Override publicvoidonClick(Viewview){ Intentintent=null; switch(view.getId()){ caseR.id.button1: intent=newIntent(TransmitDataActivity.this,MyActivity1.class); //保存String类型的值 intent.putExtra("intent_string","通过Intent传递的字符串"); //保存integer类型的值 intent.putExtra("intent_integer",300); Datadata=newData(); data.id=1000; data.name="Android"; //保存可序列化的对象 intent.putExtra("intent_object",data); //显示用于接收数据的Activity startActivity(intent); break; caseR.id.button2: intent=newIntent(); intent.setClass(TransmitDataActivity.this,MyActivity2.class); //下面的代码为MyActivity2中放入三个静态变量赋值 MyActivity2.id=3000; MyActivity2.name="保时捷"; MyActivity2.data=newData(); MyActivity2.data.id=5555; MyActivity2.name="Android"; startActivity(intent); break; caseR.id.button3: intent=newIntent(TransmitDataActivity.this,MyActivity3.class); //获取剪贴板对象(ClipboardManager) ClipboardManagerclipboard=(ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE); //创建Data对象 DataclipboardData=newData(); //设置Data对象中字段的值 clipboardData.id=6666; clipboardData.name="通过Clipboard传递的数据"; //创建字节数组输出流对象,用于将Data对象转换为字节流 ByteArrayOutputStreambaos=newByteArrayOutputStream(); //用于保存Data对象生成Base64格式的字符串 Stringbase64Str=""; try{ ObjectOutputStreamoos=newObjectOutputStream(baos); //将Data对象写入对象输出流 oos.writeObject(clipboardData); //将字节流进行Base64编码 base64Str=Base64.encodeToString(baos.toByteArray(),Base64.DEFAULT); oos.close(); }catch(IOExceptione){ e.printStackTrace(); } //获取存储文本数据的剪贴板数据对象(ClipData) ClipDataclipData=ClipData.newPlainText("data",base64Str); //设置主剪贴板 clipboard.setPrimaryClip(clipData); //显示Myactivity3窗口 startActivity(intent); break; caseR.id.button4: //获取MyApp对象 MyAppmyApp=(MyApp)getApplicationContext(); myApp.country="美国"; myApp.data.id=1234; myApp.data.name="飞碟"; intent=newIntent(TransmitDataActivity.this,MyActivity4.class); startActivity(intent); break; default: break; } } } }
Data类:这个类是可序列化的,也就是实现了java.io.Serializable接口的类。
packagemobile.android.transmit.data; importjava.io.Serializable; publicclassDataimplementsSerializable{ publicintid; publicStringname; }
在Myactivity1.java中:packagemobile.android.transmit.data;
publicclassMyActivity1extendsActivity{ @Override protectedvoidonCreate(BundlesavedInstanceState){ //TODOAuto-generatedmethodstub super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); TextViewtextView=(TextView)findViewById(R.id.textview); //获得String类型的值 StringintentString=getIntent().getStringExtra("intent_string"); //获得Integer类型的值 intintentInteger=getIntent().getExtras().getInt("intent_integer"); //获得Data类型的值 Datadata=(Data)getIntent().getExtras().get("intent_object"); StringBuffersb=newStringBuffer(); sb.append("Intent_string:"); sb.append(intentString); sb.append("\n"); sb.append("intent_integer:"); sb.append(intentInteger); sb.append("\n"); sb.append("data.id:"); sb.append(data.id); sb.append("\n"); sb.append("data.name:"); sb.append(data.name); sb.append("\n"); //在屏幕上输出传递过来的值 textView.setText(sb.toString()); } }
在Myactivity2.java中:
packagemobile.android.transmit.data; publicclassMyActivity2extendsActivity{ publicstaticStringname; publicstaticintid; publicstaticDatadata; @Override protectedvoidonCreate(BundlesavedInstanceState){ //TODOAuto-generatedmethodstub super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); TextViewtextView=(TextView)findViewById(R.id.textview); StringBuffersb=newStringBuffer(); sb.append("name:"); sb.append(name); sb.append("\n"); sb.append("id:"); sb.append(id); sb.append("\n"); sb.append("data.id:"); sb.append(data.id); sb.append("\n"); sb.append("data.name:"); sb.append(data.name); sb.append("\n"); textView.setText(sb.toString()); } }
在Myactivity3中:
packagemobile.android.transmit.data; publicclassMyActivity3extendsActivity{ @SuppressLint("NewApi") @Override protectedvoidonCreate(BundlesavedInstanceState){ //TODOAuto-generatedmethodstub super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); TextViewtextView=(TextView)findViewById(R.id.textview); //获取剪贴板对象 ClipboardManagerclipboardManager=(ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE); //从剪贴板中获取Base64编码字符串 Stringbase64Str=clipboardManager.getPrimaryClip().getItemAt(0).getText().toString(); //将Base64编码字符串编码成字节数组 byte[]buffer=Base64.decode(base64Str,Base64.DEFAULT); ByteArrayInputStreambais=newByteArrayInputStream(buffer); try{ ObjectInputStreamois=newObjectInputStream(bais); //将字节流还原成Data对象 Datadata=(Data)ois.readObject(); //将Base64编码原文和Data对象字段值显示在TextView控件中 textView.setText(base64Str+"\n\ndata.id:"+data.id+"\ndata.name:"+data.name); }catch(Exceptione){ e.printStackTrace(); } } }
在Myactivity4.java中:
packagemobile.android.transmit.data; importandroid.app.Activity; importandroid.os.Bundle; importandroid.widget.TextView; publicclassMyActivity4extendsActivity{ @Override protectedvoidonCreate(BundlesavedInstanceState){ //TODOAuto-generatedmethodstub super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); TextViewtextView=(TextView)findViewById(R.id.textview); MyAppmyApp=(MyApp)getApplicationContext(); textView.setText("MyApp.country:"+myApp.country+"\nMyApp.data.id:"+myApp.data.id+"\nMyApp.data.name:"+myApp.data.name); } }
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