[英]How to change value of variable after button click and get that value in different activity
我有一个按钮。 单击按钮时,我想将变量的值更改为3。在另一个活动中,我希望能够获取变量的值并基于该值进行一些计算。
我尝试使用getters和setters方法,并且传统上只是更改值而似乎没有任何效果。
//MainActivity.java
mButtonChoice2 = (Button)findViewById(R.id.choice2);
mButtonChoice2.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
//My logic for Button goes in here
if (mButtonChoice2.getText() == "Three"){
setDays(3);
openActivity();
}
}
public int getDays() {
return days;
}
public void setDays(int value){
days = value;
}
public void openActivity() {
Intent intent = new Intent(this, SecondActivity.class);
startActivity(intent);
}
//SecondActivity.java
public class SecondActivity extends AppCompatActivity {
private TextView textview;
private MainActivity obj = new MainActivity();
Integer days = obj.getDays();
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
textview = findViewById(R.id.program);
if (days == 3) {
textview.setText("Days is 3");
}
else {
textview.setText(days);
}
我希望SecondActivity中的textview用“ days is 3”更新textview文本
但是,它只是出错了,因为它不能正确接收整数天的值。
尝试以下更新的代码:
//MainActivity.java
mButtonChoice2 = (Button)findViewById(R.id.choice2);
mButtonChoice2.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
//My logic for Button goes in here
if (mButtonChoice2.getText() == "Three"){
setDays(3);
openActivity();
}
}
public int getDays() {
return days;
}
public void setDays(int value){
days = value;
}
public void openActivity() {
Intent intent = new Intent(this, SecondActivity.class);
intent.putExtra ("days",days);
startActivity(intent);
}
//SecondActivity.java
public class SecondActivity extends AppCompatActivity {
private TextView textview;
private MainActivity obj = new MainActivity();
// Integer days = obj.getDays();
int days=0;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
Intent intent=getIntent();days=intent.getIntExtra ("days",0);
textview = findViewById(R.id.program);
if (days == 3) {
textview.setText("Days is 3");
}
else {
textview.setText(days);
}
参考: https : //developer.android.com/reference/android/content/Intent https://www.dev2qa.com/passing-data-between-activities-android-tutorial/
只需在一个活动中声明一个静态变量,然后在第二个活动中使用它即可。
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