从我开始使用android studio开始已经过去了一个月,此时我被卡住了,必须通过一组<EditText/>
值从MainActivity
到UpdateActivity
,然后将这些值发送到Sqlite数据库以更新表。Android:将值传递给另一个活动的功能,然后传递给Sqlite数据库
我已经完成:从MainActivity
成功发送值的<EditText/>
到UpdateActivity
的<EditText/>
我也怎么做,从MainActivity
:
public class MainActivity extends AppCompatActivity {
DatabaseHelper myDb;
EditText editName, editSurname, editMarks;
Button btnUpdate;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myDb = new DatabaseHelper(this);
editName = (EditText) findViewById(R.id.UpdName);
editSurname = (EditText) findViewById(R.id.editTextSurname);
editMarks = (EditText) findViewById(R.id.UpdMarks);
btnUpdate = (Button)findViewById(R.id.btnUpdate);
btnUpdate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String MainName = editName.getText().toString();
String MainSurname = editSurname.getText().toString();
String MainMarks = editMarks.getText().toString();
Intent UpdateAct = new Intent(MainActivity.this, UpdateActivity.class);
UpdateAct.putExtra("Name", MainName);
UpdateAct.putExtra("SurName",MainSurname);
UpdateAct.putExtra("Marks", MainMarks);
startActivity(UpdateAct);
}
});
}
然后UpdateActivity
内:
public class UpdateActivity extends AppCompatActivity {
DatabaseHelper myDb;
Button btnUpd;
EditText editTextId, editUpdtName, editUpdSurname, editUpdMarks;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_update);
Intent getData = getIntent();
String Name = getData.getStringExtra("Name");
String SurName = getData.getStringExtra("SurName");
String Marks = getData.getStringExtra("Marks");
editTextId = (EditText)findViewById(R.id.editTextID);
editUpdtName = (EditText)findViewById(R.id.UpdName);
editUpdSurname = (EditText)findViewById(R.id.UpdSurname);
editUpdMarks = (EditText)findViewById(R.id.UpdMarks);
btnUpd = (Button)findViewById(R.Id.btnUpd);
editUpdtName.setText(Name);
editUpdSurname.setText(SurName);
editUpdMarks.setText(Marks);
}
什么我被困在是将这些值发送到一个名为updateData();
对于我试图直接从MainActivity
使用值UpdateActivity
但未能功能,那我就投那些<EditText/>
,并用它在函数内部但再次失败。
里面我UpdateActivity
:
..//
editUpdtName.setText(Name);
editUpdSurname.setText(SurName);
editUpdMarks.setText(Marks);
//updateData(Name, SurName, Marks);
updateData();
}
//function definiton
// public void updateData(final String Name, final String SurName, final String Marks)
public void updateData()
{
btnUpd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// boolean isUpdated = myDb.updateData(editTextId.getText().toString(), Name,SurName, Marks);
boolean isUpdated = myDb.updateData(editTextId.getText().toString(), editUpdtName.getText().toString(),
editUpdSurname.getText().toString(), editUpdMarks.getText().toString());
if(isUpdated == true){
Toast.makeText(UpdateActivity.this, "Data Updated Successfully!", Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(UpdateActivity.this, "Data NOT Updated!", Toast.LENGTH_SHORT).show();
}
}
});
}
}
应用崩溃每次功能updateData();
被调用,以确保是真正的原因我甚至有评论,也试图把它在一个处理器3000ms后运行它,正如所期望的那样,它在这段时间之后坠毁了。
通过初始化数据库来解决它。
myDb = new DatabaseHelper(this);
就像我之前提到的,_刚开始学习这个_轻松对降低成绩的人! – user5173426