我正在嘗試制作一個應(yīng)用程序，我想在其中將值從一個傳遞editText(MainActivity.java)到listView(bestFitActivity.java)另一個活動中。我的代碼的問題是它只將一個值傳遞給listView. 當我輸入一個新值時，它只會替換以前的值。MainActivity.javapublic class MainActivity extends AppCompatActivity { int i = 0; String getChunkSize; ArrayList<String> chunkSizeArray = new ArrayList<>(); EditText chunkSize; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button chunkSave = (Button)findViewById(R.id.chunkSave); Button processSave = (Button)findViewById(R.id.processSave); Button bestFitDirector = (Button)findViewById(R.id.bestFitdirector); Button worstFitDirector = (Button)findViewById(R.id.worstFitdirector); Button firstFitDirector = (Button)findViewById(R.id.firstFitDirector); EditText processSize = (EditText)findViewById(R.id.processSize); chunkSize = (EditText)findViewById(R.id.chunkSize); chunkSave.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { i++; Log.d("Manager" , "%d" +i); getChunkSize = chunkSize.getText().toString(); //Log.d("Manager" , "" +getChunkSize); if(getChunkSize == null ) { Toast.makeText(getBaseContext(), "Empty Input", Toast.LENGTH_SHORT).show(); } } }); bestFitDirector.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Intent myIntent = new Intent(MainActivity.this , bestFitActivity.class); myIntent.putExtra("chunkSizeArray" , getChunkSize ); startActivity(myIntent); } });}PS：這段代碼不完整
2 回答
藍山帝景
TA貢獻1843條經(jīng)驗 獲得超7個贊
每次單擊按鈕時，都會創(chuàng)建一個帶有新空 chunkSize ArrayList 的新活動，僅使用單個值創(chuàng)建。
您可以在每次單擊按鈕時添加到 MainActivity 中的chunkSizeArray，然后在各個 intentExtras 中發(fā)送一個計數(shù)器和數(shù)組的值。
然后從 bestFitActivity 中的所有 Intent Extra 中檢索并構(gòu)建 ArrayList。
這就是你可以做到的
public class MainActivity extends AppCompatActivity {
public static final String INTENTKEY_ARRAYELEMENTS = "arrayelemets";
public static final String INTENYKEY_ELEMENTX = "element_";
private static ArrayList<String> chunkSizeArray = new ArrayList<>();
Button bestFitDirector;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bestFitDirector = (Button)findViewById(R.id.bestFitdirector);
bestFitDirector.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
chunkSizeArray.add("Test" + String.valueOf(chunkSizeArray.size() + 1));
Intent myitent = new Intent(MainActivity.this,bestFitActivity.class);
myitent.putExtra(INTENTKEY_ARRAYELEMENTS, chunkSizeArray.size());
for (int i=0; i < chunkSizeArray.size(); i++) {
myitent.putExtra(INTENYKEY_ELEMENTX + String.valueOf(i),chunkSizeArray.get(i));
}
startActivity(myitent);
}
});
}
}
和
public class bestFitActivity extends AppCompatActivity {
ArrayList<String> chunkSizeArray = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_best_fit);
Intent mypassedIntent = getIntent();
int elements = mypassedIntent.getIntExtra(MainActivity.INTENTKEY_ARRAYELEMENTS,0);
for (int i = 0; i < elements; i++) {
chunkSizeArray.add(mypassedIntent.getStringExtra(MainActivity.INTENYKEY_ELEMENTX + String.valueOf(i)));
}
Toast.makeText(this,"The number of strings in the chukSizeArray is " + String.valueOf(chunkSizeArray.size()),Toast.LENGTH_SHORT).show();
for (String s: chunkSizeArray) {
Log.d("chunkSizeArray Value",s);
}
}
}
點擊 5 次后（點擊返回返回 MainActivity）日志為
2019-03-10 17:19:51.687 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test1
2019-03-10 17:19:56.362 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test1
2019-03-10 17:19:56.362 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test2
2019-03-10 17:19:59.877 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test1
2019-03-10 17:19:59.877 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test2
2019-03-10 17:19:59.877 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test3
2019-03-10 17:20:03.007 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test1
2019-03-10 17:20:03.007 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test2
2019-03-10 17:20:03.007 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test3
2019-03-10 17:20:03.007 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test4
2019-03-10 17:20:06.266 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test1
2019-03-10 17:20:06.266 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test2
2019-03-10 17:20:06.266 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test3
2019-03-10 17:20:06.266 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test4
2019-03-10 17:20:06.266 11271-11271/com.example.bestfitapp D/chunkSizeArray Value: Test5
添加間隙以將點擊分開
一種更簡單的方法是使用putStringArrayListExtra和getStringArrayListExtra方法，它們基本上代表您執(zhí)行循環(huán)。
所以主要活動有
public static final String INTENTKEY_ARRAY = "bestfitarray";
在 onClick 偵聽器中，您可以：-
myitent.putStringArrayListExtra(INTENTKEY_ARRAY,chunkSizeArray);
隨著
myitent.putStringArrayListExtra(INTENTKEY_ARRAY,chunkSizeArray);
在 bestFitActivity 中。
MYYA
TA貢獻1868條經(jīng)驗 獲得超4個贊
你可以做一個簡單的黑客攻擊
改變ArrayList<String> chunkSizeArray = new ArrayList<>();
靜態(tài)喜歡private static ArrayList<String> chunkSizeArray = new ArrayList<>();
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